Department of Agriculture and Immi- gration of Virginia GEO. W. KOINER, Commissioner In co-operation with the Forest Service United ^States Department of Agricnlture Henrv S. Gra\p:s, Forester SHORTLEAF PINE IN VIRGINIA The Increase in its Yield by Thinning By W. W. ASHE Forest Examiner, Forest Service RICHMOND: IJAVIS UOXroM, .SUPERINTENDENT FTPLK; PKINTING ]5)13 PLATE 1. (."rowded small pole stand of shortleaf pine about 30 years old in need of thinning. The trees are slender and clean stemmed, but irregular in size A large number of the smaller trees should be removed. Department of Agriculture and Immi- gration of Virginia GEO. W. KOINER, Commissioner In co-operation with the Forest Service United States Department of Agriculture Henry S. Graves, Forester SHORTLEAF PINE IN VIRGINIA The Increase in its Yield by Thinning By W. W. ASHE Forest Examiner, Forest Service RICHMOND: DAVIS BOTTOM, SUPERINTENDENT PUBLIC PRINTING 1913 '•p fc \1 SEP 15 19'.9 CONTKNXS Purposes and results 5- Distribution and importance <6 Names and distinguishing claaraoteristics 7 Uses of wood ^ Condition and composition of old-field stands 9s. Permanency of old-field pine stands 10 Management lii. Fully stocked and crowded stands .- 13. Understocked stands 14 Thinnings 15. Classes of trees 15. Dominant trees 15 Intermediate trees 15 Suppressed trees 16 How heavily to thin ItJ What to remove in thinning 1'^ Acceleration in growth from thinning 17 Method of thinning m Sapling stands (younger than 20 years; 18 Small pole stands (from 20 to 30 years old ) 18 Large pole stands (from 30 to 40 years old ) 19- Mature stands (from 40 to 50 years old) 19 Typical stands 20 Production of cordwood from thinned and unthinned stands 23 Maximum yield of cordwood 24 Cost of growing cordwood 2& Production of saw timber 26 Influence of density of stand upon yield of saw timber at different ages 2'' Age of cutting for maximum yield . 2« Cost of growing saw timber 2^ Value af trees and stands 32 Waste in cutting small trees 35 Lumbering and restocking 35 Isolated seed trees 3b" Cutting in strips 37 Cutting unthinned stands 37 Planting waste land 38 Returns from plantations 39 The protection of stands 41 Fires 41 Insects 43 Fungus diseases 44 It^UUSTRATPIONS Plate I. — ^Crowded small pole stands of shortleaf pine about 30 years old in need of thinning. The trees are slender and clean stemmed, but irregular in size. A large number of the smaller trees should be removed Frontispiece. Plate II. — A dense sapling stand of shortleaf pine 15 to 18 years old, but too small to be profitably thinned. While the clean condition of the floor is good, fire could do great damage to such a stand Plate III. — Understocked large pole stand of shortleaf pine 30 years old. The trees are short-bodied and knotty and will yield only low grade lumber. The best that can be done with such a stand is to cut it, leaving the most slender, clean-bodied trees for seed-trees Plate IV. — Crowded, large pole stand of shortleaf pine 40 years old, badly in need of thinning by removing the smaller pines and many of the hardwoods. Condition of larger trees, with long, smooth bodies, excellent Plate V. — 'Mature stand of shortleaf pine. Trees nearly uniform in size and ready to be cut for lumber. Groups of slender, wind- firm trees can be left- for seed trees, Plat" VI. — Figure 1. — A typical case of sustained rapid diameter growth, resulting from repeated thinnings, in a tree of short- leaf pine which was overcrowded for many years. Wood of .'such a tree is free from large knots, and its stum page is worth $8 a 1,000 board feet under a cost of operating of $12 li'igure 2. — Stem of a small sprout sapling of shortleaf pine, crooked and scarred at the neck as a result of the original seedling having been killed to the ground by fire. Stump and root rots gain entrance through such scars. Shortleaf Pine in Virginia The study upon which this report is based was undertaken by the Forest Service in co-operation with the State of Virginia, the worlc being done under the direction of tlie officer in charge of State Co-operation in the Forest Service. By ithe terms of the co-operative agreement, the State is authorized to publish the find- ings of the investigation. PURPOSES AND RESULTS. At the request of Hon. C. A. Swanson, Governor of Virginia, the Forest Service, United States Department of Agriculture, in the autumn of 1909, made an examination of the second-growth shortleaf pine in old fields in the middle portion of Virginia. The cost of this work was borne jointly by the State of Virgiiiia and the Forest Service. The examination includevl.a detailed investigation of stands of pine in old fields in Mecklenburg, Lunenburg, Brunswick, and Hanover counties, which was supplemented by a general examina- tion of the stands in other counties in the middle part of the State. Its scope was: (1) To ascertain the condition of the old-field stands and the value of their timber for lumber uses; (2) To determine the eli'ect of lumbering on the future yields of the stands and to ascertain whether conservative methods of cutting could be employed profitably; (3) To determine the yield of stands of different ages; (4) To recommend methods of thinning and cutting to ac- celerate growth; (5) To devise methods of protection for young growth. The conclusions reached as a result of the investigation can be summarized as follows: Shortleaf i)ine is the most important tree in twenty south- central counties, but the yield from the pine lands is low because there is neither protection nor a definite system of cutting. The yield can be greatly increased and the quality of timber improved by a regular system of management. (1) Better protection against fires and insects is required in most stands. Young stands, especially while in process of stocking, C SHORTLEAF TINE TX A IKCIX lA Slitter most from fires. Older stands are most endangered by in- sects. Protection against fire may be secured by means of fire lanes, posted warnings, restriction of nigtit hunting, and patrol during dry seasons Avhen neighboring lands are afire. The danger of loss from insects may be reduced by making frequent thinnings and by removing or by cutting infested trees. (2) The average stand of pine is far too thinly stocked. This is due to insufficient natural seeding and to the thinning of young stands by fire and of older stands by insects. The yield of such thinly-stocked stands is considerably less, and the grade and vahie of the timber is lower, than from thickly stocked stands. (3) Crowded areas occur in nearly all stands, and some stands are crowded throughout. Such crowded plots can be greatly im- proved by thinnings. The ett'ect of thinnings is to accelerate growth, hasten maturity, and produce a superior quality of timber. The beneficial results of thinnings decrease with the age of the stand, but stands as old as forty-hve years respond to them well. (4) Where naturaf seeding has not formed dense stands with- in ten years, the stocking can be completed by the planting of seed; and, where natural seeding does not take place, whole areas may be seeded. Stands restocked in these ways can be expected to yield fully as Avell as the best natural stands and to return a fair rate of interest on their cost. If management is applied, that is, if young stands are pro- tected, full stocking secured, and the stands subsequently thinned, the yield of saw timber fi^om a 40-year-old stand can be more than doubled and its value greatly increased. Shortleaf pine is already one of the chief sources of building material on the farms. Pair- thermore, the farms have more timber than is required for then- own support, so that as the general demand for coarse lumber in- creases and its price rises, shortleaf pine in farm woodlots can be made an important source of commercial timber and a means of permanent income. DISTRIBUTION AND IMPORTANCE Second-growth or old-field shortleaf pine is the most important tree of middle Virginia and the Piedmont, south of the Rappa- hannock, in which region it probably occupies more than one-half of the total forest area and more than three-fourths of the farm forest area. It forms the dominant growth on more than 3,000,000 acres, on which it occurs either in, pure stands or, more commonly, SlIORTLEAF PINK IX VIKCIXIA 7 with u slight mixture of other pines and of seedling and sprout hardwoods. It meets with least competition and forms the i)urest second-growth stands in the tier of southern counties west of Lun- enburg county. It is not common iu)rth of the Eappahannock river, and is infrequent on the Blue Eidge mountains and in the Great Valley, while in I'idewater Virginia it grows only on the best drained clay soils, and in these sections, on account of the com- petition of other species, its second grow^th seldom occurs in pure stands. Xames and DlSTlNGUISniXG ClIARACl'ERISTICS Shortleaf pine is also and more generally known as rosemary pine, spruce pine, and yellow pine. The original growth is fre- (juently distinguished from the second growth in old fields under the names of forest or woods pine. I'his tree is not to l)e confused with scrul) or jack pine, which is also called spruce pine. Scrub pine is a smallei- and in- ferior tree with a limby stem and smooth, scaly bark. It is largely replacing shortleaf pine in old fields in the northern portion of the State and in the upper edge of the Piedmont in and near the mountains, and is occasionally found mixed witli shortleaf pine •southeastward as far as Brunswick county. Xor is it to l)e con- fused with loltlolly pine, which is kncnvn in extreme southern \'ir- ginia as shortleaf pine and. where it occurs near the cuast. as long- leaf, swamp, foxtail, or slash pine. Lol)lolly i)ine is the common pine on sandy soils in Tidewater Virginui. but it extends westward in association with shortleaf pine to T)runswick. Chesterfield and Louisa counties. The northern i)itch. bull, or black pine of the mountains, which is yet another tree, seldom forms second growth in old fields. The cone and leaf differences of these trees will be a further lielp in sei)arating them: Shortleaf pine has cones (burrs) seldom more than 1 l-'2 inches long, and slender, straight neeflles. two or three together, twice as long as the cones. Scrub pine has cones of about the same length as tho^e of shortleaf pine (1 1-2 inches) but they are relatively broader. The needles are stout and twisted, with never more than two together, and are about the same length as tlie cones. Freciuently the cones of sci'ub pine and shortleaf pine remain on the ti-ees for nuuiy years after opening. 8 SHORTLEAF PIXE IN VIRGINIA Loblolly pine has large cones, from 3 to 4 inches long. Its needles are borne in threes and are about twice as long as the cones. The cones of this species usually fall during the second summer, but sometimes they persist for several years. Uses of Wood The timber of second-growth shortleaf pine is largely sap- wood. The formation of heart wood does not begin until the trees are about twenty-five years old. For many years thereafter the heartwood is limited to a small core, and more than two-thirds of the volume of trees fifty years old is still sapwood. The most im- portant uses for the wood of the shortleaf pine are for building lumber, fuel, slack cooperage, box lumber, headings, and crates. The wood contains too much resin to be a desirable material for paper pulp stock without special treatment, although it is used to some extent for this purpose. On account of its softness it is not suited for railroad ties if the traffic is hea\'y\ and, when used for this purpose should be made more durable by preservative treat- ment. 'J'he large proportion of sapwood in the second-growth tiin- ber renders it undesirable for shingles, for which the durable lieart- wood of the old growth was extensively employed ; and imfits it for other uses requiring exposure to the weather, unless it is thoroughly IdJn-dried and painted. Logs more than fourteen inches in dia- meter from trees with clear boles yield lumber suitable for ceiling styles and panels of doors, sashes, window frames, interior wood- work, and also for flooring if rift sawed. Timber suitable for such uses must come not only from comparatively large trees, but from trees which early cleaned their stems and formed wood in the lower two-thirds of the trunk free of Imots. That part of the tree which can be converted into lumber of this kind should command, on the basis of $25 for the finished lumber, a stumpage price of not less than $10 a thousand board feet. Unless the pri<'e of cordwood. stumpage is proportionately much higher than that of saw timber stumpage, the greatest profit from a crowded stand will be secured by reserving the larger trees for saw timber, and in the meantime thinning or culling the small- CvSt trees for cordwood, stave stock, box boards, bolts, and similar purposes, for which small material is suited. If only selected trees are retained for saw timber they should be allowed to attain a large size in order to produce timber of high quality. PLATB II. A dense sapling stand of shortleaf pine 15 to 18 years old, but too small to be profltably thinned. While the clean condition of the floor Is good, fire could do great damage in such a stand. SIIORTLEAT PINE IN VIROINIA V CONDITION AND COMPOSITION OF OLD-FIEi^D STANDS As early as 1735 it had become a fixed part of the farming system of middle Virginia to clear new ground each year and to abandon to tallow a parcel of the oldest and most worn farming land. The land tiius turned out was rapidly colonized with pines through seed blown by the wind from old trees nearby. When these pines had become large enough and the humus had been re- stored to the soil through them, the land was usually cleared again. Such a system of rotation of timber and cultivated crops was pos- sible only in a region where land was abundant and cheap. It was due in part to the lack of local markets, which made it necessary to export a large portion of the crops and therefore to produce them as cheaply as possible, regardless of the eli'ect upon the soil; and in part to the fact that these soils were not natural grazing lands, and the depleted humus could be renewed naturally and cheaply by the replacement of the native pines. Some of the existing groves of old-held pine thus originated before the Revolutionary W^ar. Most of them, however, are younger, having originated dur- ing and just after the Civil War or in the subsequent periods of agricultural depression about 1880 and 189-2. These stands are consequently of all ages; from the youngest, just in process of stocking land which has been turned out during the past decade, to those more than 100 years old. Stands between tifteen and forty-five years old are, however, the most numerous. Such old-field stands were thus established naturally, and no efforts were made by the owners to increase their density Avhen they wei-e too open or to i)rotc('t them, while young, from fire. They have seldom been thinned judicionsly for improvement. As a result, they vary widely in density. Small tracts are usually well-stocked, since, if seed-bearing trees were nearby while stocking was taking place, seeds were in a few years scattered uniformly over the entire tract and such small tracts were often protected from fire by fences, or by adjacent cultivated fields. The trees in such well-stocked stands are slender and clean-bodied, with small crowns. The average tract, however, is poorly stocked. The trees are isolated, individually, or in irregular groups, and conseciuently short-bodied, knotty, and coarse-grained. This open condition of many of the stands is due to the fact that seed trees were too few or too distant while the stocking Avas in progress, or to the fact that the fields became grassv and the seedlings Avere killed by 10 SHOKTLEAF PINE IN VIRGINIA fires that burned the grass. Scattered advance growth frequently has borne seed and so stocked the gaps. Such stands are irregular in age and size. Many of the older stands have been irregularly and often heav- ily cut for poles, cordwood, and even sav^logs. Most stands of sap- ling or larger size are too open for the best growth of the trees and for the highest financial returns. The proportion of shortleaf pine in the old-field stands varies. -North of the Eappahannock river the proportion of scrub pine mixed with the shortleaf increases, until in Fairfax county and the lower end of Prince William county it largely replaces shortleaf pine. It is also largely mixed with shortleaf pine in stands near the mountains. In the shortleaf pine stands in the eastern ends of Hanover, Chesterfield and Brunswick counties, there is a large proportion of loblolly pine, which entirely supplants the shortleaf farther eastward. South and southwest of Hanover county the only pine in the field stands is the shoi-tleaf, but species other than pine form part of the mixture in a varying proporticm, though they seldom make up more than ten per cent, in stands younger than thirty-five years old. In young stands these associated species vary Avith the kinds of seed-trees nearby. On lower slopes they are usually maple, poplar, sweet gmn. and the oaks; on hilltops they are red cedar, oaks, hickory, black gum. persiniinon. cherry, thorn, sassafras, and dogwood. Permanency of Old-Field Pine Stands As the field pine stands become older. es]:)ecially after they have passed the thirty-fifth year, their crown cover tends to thin, and this favors the growth of the oaks and hickories, which come in from seed dropped by squirrels, crows', jays. etc.. and are better able to grow beneath the cover than are young pines. Even after the pine in the stand begins to seed the proportion of these broad- leaf species continues to increase, since the young pines can come in only when an extensive opening is made by the death of a large \Vu\e. There is thus a tendency toAvard a gi-adnal re-establishment of the oi'iginal forest type Avhich prevailed l>efore the land Avas cleared, namely, a mixture of oak. hickory, black gum. and pine, with pine forming a small proportion on the best soil and a large proportion— frequently more than half the number of trees — on the poor, dry or sandy soils. The pure pine stands are. therefore, a temporary type. Avhich in time Avill be re])laced by the permanent mixed-growth type. SHORTLEAF PINE IX VIRCIXIA 11 It is not Jin invariable rule that "•hardwoods follow pine" after nittmg or that "pine follows hardwoods'" after cutting or clearing. But pure pine usualty forms the second growth if there is no shade or cover, as in old fields or on hardAvood land which has been cut clear in late summer or early antumn. when the sprouting power of the hardwoods is low. If seed-bearing trees are near, such open land, whether in field or forest, is captured in a few years by pine, by means of its abundant, light seeds which are widely scat- tered by the wind. The heavy seeds of oak, hickory and black gum. which are Carried iai'gely by birds and squirrels, are dis- seminated too slowly and irregularly to enal)le such species to compete successfully witli pine in stocking nearby open lands. Un- der these conditions, pine usually follows oak. On the other hand, pine is unable to establish itself beneath dense shade, whether of pine or of hardAvoods. For this reason 3'Oung pine growth is seldom found under the trees except in older open pine stands. The seeds of hardwoods, however, are dropped from year to year in such stands and germinate; and the seedlings, through their persistency and ability to endure shade, Avill survive in shade in which a young pine can not live, although their growth in this case is extremely slow. When the large pines are cut, these stunted hardwoods, responding to improved conditions of light and root space, grow rapidly and if they are numerous they form the larger part of the growth which follows the pine. in those portions of the State in which it occurs, scrub pine affects the permanence of the shortleaf pine stand on medium soils even UKjre than do the hardwoods. Scrub pine seeds ])rolifically, when much j^ounger and smaller than siiortleaf pine, and the seed- lings are tolerant of far more shade than those of the shortleaf. For these reasons, it not only excludes the shortleaf from old fields Avhich are in process of stocking, but it successfully competes Avith the young hardwoods in occu])ying openings in stands ot shortleaf pine in wliich the coAcr is too heavy for shortleaf seed- lings to exist, and thus in part succeeds the shortleaf in shortleaf stands. By reason of this aggressiveness, scrub pine is so completely replacing shortleaf pine over large areas in the northeastern paii of the State and near the Blue Ridge that the economic range of shortleaf pine is being restricted. 12 SHORTLEAF PINE IN VIRGINIA MANAGEMENT Forest managenient as applied to old-field stands may be sum- marized as the use of any methods of restocking, cutting, or thin- ning which will reduce the cost of growing timber or add to the value of the timber grown. Natural stands are usually either understocked, at least in certain phases or during certain periods of growth, or else over- crowded. The maximum growth is obtained by maintaining such a num- ber of trees to the acre as will utilize the full capacity of the soil and at the same time secure the best development of the individual trees. Understocked stands do not use the full capacity of the soil and must be filled out to the required density by planting in the thin places. In crowded stands, on the other hand, the indi- vidual trees are retarded; they must be thinned in order to make them grow at their best rate. These requirements of the stand are discussed in conne-ction with the subjects of thinnings and planting. Another phase of management is cutting at the period of ma- turity as determined by either maximum yield or value. The rate of growth or accretion of a stand is not the same at all ages. The yearly growth rapidly increases from nearly nothing to a maxi- mum, then slowly declines. When the rate of annual growth be- gins to decline, a loss in yield is entailed if cutting is deferred. The time at which the maximum of the average annual yield is obtained varies with the size of the timber which is desired; it would not be the same for lumber, which requires large timber, as for cordwood, for w-hich small timber can be used. But while it is desirable to obtain the maximum annual yield from a stand, the cost of production is a factor Avhich cannot be neglected. The cost of production embraces the interest on the investment, the taxes, superintendence, protection, and the making of improA^e- ment cuttings and thinnings. As far as the needs of ow^ners and the market conditions allow, a stand should be cut at financial maturity, that is, when it yields the best, returns on the investment. These phases of management are considered in connection with yields of stands at different ages, and with the cost of growing timber. One of the most important considerations in manage- ment is the method employed for obtaining a prompt renew\al of the stand in order to prevent the loss of interest on the investment by the idleness of the land. SHORTLEAF PINE IN VIRGINIA 13 Protection of stands from fire, from insects, and from fiin^is diseases is necessary to insure fully stocked stands and sound timber. The figures relating to the gi'owth and yield of shortleaf pine are based on stands which are growing on soil formerly covered with forests of shortleaf pine mixed with white oak, southern red oak (Querc'us digit ata)^ black oak, and white hickoiy. The rate of growth on such sites is regarded as the average or tusual rate. Where the pine now grows on soils which were formerly covered with forests of shortleaf pine mixed with post oak, with black-jack oak, or with Spanish oak {Quercus coecinea), or with a large propor- tion of these oaks together with other oaks, the rate of growth and the yield of the stands will be considerably lower than that given. Fully Stocked and Crowded^ Stands A stand is fully stocked when it contains all the well-grown, vigorous trees which the soil can support. This number decreases with the age of the stand and tlie consequent increase in the size of the trees. In a natural twenty-year-old stand of shortleaf pine the number to the acre should exceed 1,500; at forty years it has decreased to about 750; at sixty years it has fallen to less than 450. This reduction of the number of trees in a stand progi-esses nat- urally. As the trees become older and larger, their crowns spread and their roots extend m search of food and moisture. Com]:)eti- tioii for light, food and moisture ensues, and this in turn results in the dying of the smaller and weaker trees, which are overtopped and crowded out by the more vigorous ones. A fully-stocked stand, in which natural thinning is taking place rapidly, is crowded (plates I, II and IV). At any age the fact that a stand is crow^ded is indicated by a close crown cover and the presence of many dead trees and slender live trees with narrow crowns. In a young stand of this character less than thirty-five years old the crowding is so great that the crown of each tree al- most touches the crowns of its neighbors and direct sunlight hardly reaches the soil. The shade is sufficient to prevent the start of young trees and most shrubs beneath the pines and the carpet of pine needles is so thick as to exclude grass, while small dead trees are numerous. In stands more than thirty-five or forty years old there is a wider distance between adjacent crowns, due to the rapid dying of the larger of the slender narrow-crowned trees. This opening of the stand admits more sunlight, and young oaks, hick- 14 SHORTKEAF PINE IN VIRGINIA ories, and other trees, as well as many shrubs, begin to gi-ow be- neath the pines. Dead trees and live trees with naiTow crowns are not so numerous as in younger stands. The mat of pine needles is thinner in the older stands and grass is able to spring up. A fully-stocked young stand of shortleaf pine has, therefore, a dense crown cover. In both young and old stands, if they are fully stocked, there are slender trees with narrow, spry crowns and aead trees which have been crowded out, though the latter are mcjre abundant in the young stands. Whether a stand is crowded and in need of thinning may be determined by the greater or lass abund- ance of crowded and dead trees, considered in connection with the age of the stand and the normal density of the crown canopy at a given age. Understocked Stands The average stand of shortleaf pine in middle and Piedmont Virginia, however, instead of being too densely stocked, is too thinly stocked. When the crowns do not interfere, or are round- topped with practically horizontal lower branches, the stand is to'o open for best gi-owth. Young and even middle-aged stands are frequently open, but their wide-spreading crowns eventually close and form a dense crown cover like that of a fully-stocked stand. But in this case dead trees and slender overtopped trees are absent : the crowns of the trees are too round and wnde-spreading; the stems are too short and limby: and the number of ti-ees to the acre is much less than in fully-stocked stands of the same height. (Table 9). Under- stocked stands of this kind do not require thinning. Moderately understocked young stands usually become crowded early enough to reduce some of the evils of understocking, but the stems of the trees are never so tall and free from limbs and Imots as those which develop when there is crowding all through the life of the stand and their total yield is usually less than that of a fully- stocked stand. (Plate III). Young understocked stands should be filled out by planting. In nearly every stand, however, there will be found at least groups of trees which will be benefited by thinning. The presence in the stand of numerous small dead trees and slender trees with spiry crowns is a clear indication that thinning is needed. SHOKTLEAF PINE IN VIK(JINIA l6 THINNINGS The objects of thinnings are, first, to accelerate the gi'owth and shorten the time necessary to bring the stand to maturity, and, second, by removing defective trees ft) produce a mature stand formed of perfect specimens and so increase the yiekl of kiinber. The elimination of the weaker specimens by natural process takes place too slowly for the best development, because the growth of the trees which are ultimately to survive is retarded by the pro- longation of the struggle for light and food. Yet limited crowd- ing is necesvsaiy at certain periods to force height growth and to develop long, straight stems, reasonably free from limbs. More- over, the number of trees to the acre largely determines the volume of the yield and has an important bearing on the value of the trees. Usually the crowded stands produce the greatest volume of w(M)d at all ages; but when the size or diameter of th<' individual trees is of primary importance, as in the prodiu-tion of saw logs, less crowding is desirable. By means of judicious periodic thin- nings, it is possible both to favor competition and to relieve over- crowding and in this way gi-eatly to accelerate the growth of the remaining trees. Such thinnings reduce the number of trees, but they produce equally tall trees of much larger diameter, with straight, clean stems and but little taper. It is commonly held that if the larger trees are removed as they come to merchantable size the smaller trees will make accelerated growth. This is un- questionably true of many species and it is true also of short- leaf pine under thirty years old, but in pure old stands of short- leaf pine in Virginia the crowded and suppressed trees recuperate so slowly that it is not profitable to thin the stands in this way after they have passed the age of thirty-five, years. Classes of Trees Before thinnings can be intelligently made, the classes of trees iii a stand must be known and their relation to the growth of the stand understood. The live trees in a second-growth pine stand can be separated easily into three classes: DominaM Trees.— "TliQ^Q are the tallest and thriftiest speci- mens with the largest crowns. Their growth is rapid, both in height and in diameter. Intermediate Trees. — These are the slender, clean-bodied trees, with narrow, compressed crowns which are nearly as tall as the Iti SHORl-LEAF PINE IN VIRGINIA dominant trees. Their height growth is rapid, but, on account of their small crowns, their diameter growth is slow. Besides be- ing unable to make good volume growth themselves, they retard the growth of the dominant trees. Suppressed Trees. — These have fallen behind in height and are so much lower than the other trees that direct sunlight is largely excluded from them. They interfere very little with the growth of the larger trees. When overshadowing and suppression pass a certain point the trees die. Three-fourths of the dead trees are in the sup- pressed class, but intermediate trees also die from overcrowding. Dead trees exert no influence upon the growth of the stand. When possible, however, they should be removed, since they contribute to the danger of disease, insects, and fire. HOW HEAVILY TO THIN Thinnings must be heavy enough to provide more light and crown space, and more root space and soil moisture for the trees that are left, yet they must never be heavy enough at one time to admit too much sunlight and cause the crowns to spread unduly, with a sacrifice in the rate of height growth. Too heavy a thin- ning results in temporary understocking and produces the oppo- site of the result desired. To be most effective, thinnings should begin when a stand is twenty years old, and should be light and frequent. Early thin- nings prevent the crowns from crowding before their s\anmetry is destroyed, and yet maintain sufficient crown rivalry to secure continuous height growth and promote the rapid shedding of the lower limbs. Before removing any tree, it is necessary to con- sider how its removal will affect the remaining trees, not only un- til the next thinning, but until the stand is mature and the trees are merchantable. Thinnings should be made not less often than once every ten years. Even with ten-year intervals cuttings have to be too heavy for the best interest of the stand and excessive crowding takes place before a thinning is repeated. An interval of five years is recommended as the most desirable. This develops the full value of the stand, and also allow^s the cutting of enough cord wood from the thinnings to pay for the work. A careful observer will be able to lengthen the interval if the cost of thin- nings requires it. ^1- -■\. '^'''-^iil J^^^L- Pl.ATE 111. Understocked large pole stand of shortleaf pine 80 years old. Tte trees are short-bodied and knotty and will yield only low grade lumber. The best that can be done with such a stand is to cut It, leaving slender, clean-bodied trees for seed trees. SHORTLEAF PINE IN VIKOINIA 17 WHAT TO REMOVE IX THINNING Thinnings should remove such suppressed trees as are not necessary to complete the crown cover, since they have made their growth and exert little or no influence on the growth of the large trees. Species of lower value, like gums, post oak, maple, sassa- fras, and scrub pine, should also be cut, unless they are needed to keep the crown cover complete. Funky or diseased trees should be removed from stands of all ages. Short-bodied, crooked, loiotty, forked, or otherwise defective pine trees should be cut from younger stands, but should be left in old stands when their removal would make openings wdiich would not be filled by the spread of the surrounding crowns. Enough of the intermediate class should be removed to provide growing space for the trees that are left. The trees which are removed should l)e selected evenly through the stand. If several adjoining trees are removed, an opening is left w^hich will be too long in closing. If trees are left in groups, excessive crowding in the interior of the groups will follow, and this will result in the loss by shading of the in- terior branches and unsymmetrical development of the trees. Wlien there is a choice the trees which nre left for permanent growth should have well-developed and symmetrical croAvns. ACCELERATION IN GROWTH FROM THINNING Until they are thirty or even thirty-five years old, the inter- mediate as well as the dominant trees of shortleaf pine stands re- spond vigorously and rapidly to thinnings by accelerated growth. In older stands, the recuperative power of the intermediate trees declines and the recovery from the effects of overcrowding is slow. The recuperative power of the dominant class, however, is main- tained until the trees are sixty years old, when the period of rapid height growth is well past and crown isolation has taken place. The ability of the intermediate trees m young stands to recover rapidly from the effects of close crowding, permits the cutting of the largest trees in such stands and the leaving of the slender, clear-stemmed intermediate trees to form the mature stand. In Plate VI, fig. 1, which shows the cross section of a stem of shortleaf pine, is to be seen the results of accelerated and sus- tained growth which are due to repeated light thinnings. The crowded condition of the inner rings of growth show that the tree was a slender, intermediate tree before its crown was freed by the -j^g SHORTLEAF PINE IN VIRGINIA original thinning, made, as shown by the number of wide rings, forty-seven years before the tree was cut. Several thinnings, made since the original thinning, have prevented any marked decline in the comparatively rapid rate of growth which took place after the crown of the tree was originally freed of overcrowding. The rate of growth is one inch of radius every eleven years, or about one inch in diameter every five years '(the bark thickening as well as the wood),— an excellent average rate of gi'owth to seek to main- tain in the trees of a stand. It produces timber suitable for the highest classes of uses. METHOD OF THINNING The several thinnings are for the benefit of the final cutting and unless the thinnings are made at a profit, the yield of the hnal cutting must be far heavier as a result of the thinnings m order to make them worth while. In young stands then, it is possible to distribute a portion of the thinnings m the dominam class; in old stands, thinnings must be largely restricted to the suppressed and intermediate classes. Stands more than twenty years old, which have never been thinned, require heavier thin- nings than stands of the same age which have been thinned pre- viously. ■ SapUng Stands {Younf/er than Ttceni/ Years).— Thummg^ ot sapling stands are seldom possible on account of the expense of making them and the small amount and poor character of the wood obtained. Under average conditions of growth, the wood which could be cut in a thinning in such a young stand would be from two to four inches in diameter and would make only a poor quality of fuel. Thinnings at this age are not recommended unless the wood can be used. (Plate II). Small Pole Stands {From Tioenty to Thirty Years Old).— A crowded stand twenty-five years old contains a number of large trees eight or nine inches in diameter breasthigh, and a few even ten inches; many of which are in the advance growth, two or more years older than the average age of the stand. Such trees are fre- quently bushy and very limby, with wide-spreading crowns. Usu- ally ail of the nine and ten-inch trees in such a stand and many of the eight-inch trees can be cut. These will furnish a small quan- tity of saw timber. In addition to the large trees, all of the trees below four inches, and usually about one-half of the five-inch trees can be removed. If no previous thinning has been made, about SIIORTLEAF PINE IN VIRGINIA 19 200 trees five inches and larger could be cut to the acre. These should yield about ten cords of wood, of which the material above nine inches might be sawed into about 500 board feet of lumber. About 900 trees should be left to the acre. A thinning in a twenty- year-old stand should yield much less, and one in a stand more tnan twenty-five years old should yield more and leave fewer trees per acre. At these ages trees are making very rapid growth, and the branches of the crowns are sharpiy ascending, so that com- paratively large openings are more quickly covered than in older stands. For this reason thinnings at this period present no seri- our difficulties, hut it is desirable even in making a thinning at this age to have in view the trees which are to form the final stand and these should be the tree with very slender and clean stems, that will yield several logs, and from which lumber can be sawed free or nearly free from any except small knots. For the relative value of these trees compared %ith the larger dominant trees in a stand, see table 16. {Plate I). Large Pole Stands {From Thirty to Forty Years Old).— AW trees below six inches, most of the six-inch trees, and some of the seven and eight-inch trees, should be removed from a normal thirty-five-year-old stand. If no previous thinning has been made, not less than 200 trees could be cut, many of which would, how- e\'er, be five inches or less in diameter. If a thinning has previ- ously been made, there would be fewer trees to come out. A first thinning at this time should yield from fourteen to seventeen cords to the acre. Fewer trees are removed than in thinnings in y( unger stands, and greater judgment must be used in making selections. The method of cutting in strips can be economically used only by farmers who either do their own logging or who can ])ersonally superintend it. (Plate IV). Mature Stands {From Forty to Fifty Years Old). — If a stand of this age has been previously thinned, about ninety trees to the acre would be available for removal, comprising a few six-inch trees which could not have been removed earlier without making undue openings in the crown cover, many seven-inch and eight- inch trees, and some nine-inch trees. If it were a crowded stand, not previously thinned, from 100 to 200 trees to the acre might be taken out, with a yield of not less than ten cords of wood per acre. However, unless the stumpage value of trees from fourteen to sixteen inches in diameter is greater than that of trees from twelve to fourteen inches, a size which the trees reach when about 20 SHORTT^EAF PINE IN VIRGINIA forty-five years old, timber is produced at the lowest cost by cut- ting when the stand is about this age (see tables 12 and 17). Under ordinary conditions, the stand would be cut for lumber, and not thinned, at this period. (Plate V). This method of thinning crowded stands is based on the average crowded stand. Typical Stands. — Table I shows approximately the average number of trees of each diameter from four inches up, which were found in iiTegularly thinned stands growing under a\erage condi- tions. This table is approximately correct for the average of a number of stands, but any individual stand at a given age will probably show considerable variation from it, both in the total number of trees per acre and in the number of trees in each class, since slight diii'erences in the quality of the soil atfect the number of trees to the acre at any age, and the degree of thinning in- fluences both the number' of trees and their size. It shows, how- ever, the rapid elimination of the smaller trees, which are the ones which should be chiefly removed in the thinnings, and it will serve as a guide to indicate about the number of trees of each size which should be taken out at each thinning. The stands which have been grouped as thinned stands in some cases -were undoubtedly natur- ally thinly stocked and their density has been further affected by artificial thinnings. For this reason the favorable conditions of these stands can not be entirely ascribed to thinnings. TABLE 1. Approximate number of trees four inches and over in diameter to the acre in unsystemxitically thinned stands of shortleaf pine (the twenty-year- old stand is unthinned). Age of DIAMETKB BKKAST HIGH— INCHES stand Years 4 5 6 7 8 9 10 11 12 13 U 15 16 I 17 18 Total 20 1 600 400 300 50 10 1,360 25 203 278 228 154 92 10 5 . . 970 80 70 170 176 136 106 69 25 10 1 . 765 35 2 7G 121 111 118 87 46 23 9 2 615 40 8 S4 91 115 8S 58 37 20 8 1 505 45 28 63 97 74 64 46 30 13 4 1 420 50 6 34 70 63 63 50 37 21 9 2 355 55 12 34 48 53 52 41 26 15 7 1 289 60 2 18 33 42 42 42 33 21 12 5 250 65 10 17 30 36 3H 35 26 16 9 3 218 70 • • ^ 11 21 27 31 32 28 20 14 7 1 195 SHORTLEAF PINE IN VIRGINIA 21 Table 2 shows for two stands about forty-five years old the ettect of thinning in increased board yield and in the distribu- tion of diameter classes. One is a crowded stand which has never been thinned; the other has been thinned for fifteen years in a desultory manner. Had the thinnings been systematically made, better results would have followed. The large number of trees between ten and fifteen inches in diameter in the thinned stand is noteworthy. TABLE 2. Effect of thinning on hoardrfoot yield of shortleaf pine and the distrihu- tion of diameter classes {two stands about forty-five years old). Diameter of Trees Breast high Number of Trees of Each Diameter to the Acre Unthinned stand Thinned stand 5 6 7 8 9 10-12 13-15 Total live trees Dead trees (all diameters) Yield in board feet from trees 9 inches and over in diameter Cords of stem wood with bark to the acre . . . 16 8 52 10 163 32 124 38 112 ;;2 84 74 5H 132 8 18 620 344 176 16 12,740 18,770 61 50 Table 3 shows the average height of the trees in stands at different ages, and the average diameter of all trees in unthinned and irregularlv thinned stands : 22 SHORTLEAF PINE IX VIRGINIA TABLE 3. Average height and average diameter of all trees in fully-stocked stands of shortleaf pine. Age of stand Years Avprage Height of Merchantable stand Avebagh; Diameter of all Trees Unthlnned crowded stands Inches Thinned stands 20 32 4.0 4.0 25 87 4.8 5.3 30 42 5.5 6.4 35 47 6.2 7.3 40 61 6.7 8.2 45 55 7.3 8.9 50 68 7.7 9.6 55 61 8.1 10.1 60 63 8.5 10.7 Table 4 shows the number of trees nine inches and over in diameter breast high in unthinned and irregularly thinned stands, and the average diameter of such trees. TABLE 4. Average diameter and number of trees nine inches and over in fully-stocked thinned and unthinned stands of shortleaf pine of different ages. Crowded Unthinned Stands Age of stand Number of Trees per Acre Average Diameter of Trees Thinned Stands Number of Trees per Acre Average Diameter of Trees 20 25 1 0.1 16 9.3 30 7 9.8 105 9.6 35 47 95 167 10.0 40 88 96 207 10.4 45 125 98 232 10.8 50 156 9.9 245 11 I 56 182 10.1 243 114 60 200 10.3 230 11.7 65 213 10.5 208 12 70 210 10.7 192 12.8 SIIORTLEAF PINE IN VIRGINIA 23 PRODUCTIOX OF COTU)W()()D FKOM THINNED AND UXTHINNED STANDS The yield of corchvood" is determined" rather by the number of trees than by the size of tlie individual trees. The most crowded stands usually yield most heavily, and the yield appre- cial)ly declines as the stands become more open. This has a great influence upon the yield of old stands, since after the thirty-fifth year there is practically no increase in the yield in cords of un- thinned stands, on account, of the rapid dying of the smaller tiees. For this reason, thinnings are not so profitable for the production of cordwood as for the production of saw timber; though the trees which would die are saved, and some additional gi'owth is secured. If regidar thinnings are made at intervals of five years, then at the age of forty-five years the increased yield, including the thin- nings, is only thirty-three per cent., as against an eighty per cent. TABLE 5. Yield of thmnecl and unthinned stands in cords — Trees three inches and over in diameter. Unthinned Stands Thinned Stands-Y] ELD OF THI nnings stand Voliiine ill Different Ages Volume of stand be lore eacli Thinning Number o f Trees which can be rem<.v - d in each Thinning A p p roxi- mate average diameter of Trees removed Volume of Trees removed in each Thinning Total of all previous ThiniiiDgs at any Cutting period Total of rhin- nlngs and Stand* Years (1» Cords Cords (4) Inches (5) Cor (fi) Cords (7) Cords (8) 20 47 47.0 930 3.3 6 I 47.0 25 57 52.0 205 4.5 5.1 6.1 58.1 30 6r 57 150 5.0 5.0 11.2 68.2 85 64 60.0 110 5.5 48 16 2 76.2 40 6t 60.0 85 6.0 4.3 210 81.0 45 64 59.0 68 H.5 40 25.3 S4.3 50 63 57 55 7.0 3 6 29 3 86 3 55 61 54.5 45 7.6 :-;2.9 87.4 ♦Columns is the sum of columns 3 and 7. * Unless otherwise stated, all references to cords are to standard cords of 128 cubic feet, and the corded wood is measured with the bark on. Standard cords can be converted into long cords of 160 cubic feet by dividing by 1.25 or by multiplying by 4-5. Either standard or long cords with bark can be converted into cords without bark by multiplying by .77, if the wood comes from trees which average less than 7 inches in diameter, or multiplying by .82 if the trees average a larger diameter. 24 SIIOKTLEAF PINE IX VIIUilNIA increase obtained at the same age by the thinning for lumber. Unless the value of cordwood increnses with the diameter of the wood (as it should if the wood is used for heading or stave bolts) no added value per cord is secured by thinnings. The yield in standard cords, stem wood with bark, of thinned and unthinned stands of shortleaf pine of ditferent ages is shown m Table 5. . Table G shows the approximate number of trees to the acre in crowded stands of ditferent ages, and in thinned stands. The dif- ference between the number of trees in an unthinned stand and in the same stand five years after it has been thinned indicates approximately the number of trees which should be removed from the unthinned stand. In practice, it probably would be best to make two or more thinnings before reducing the number of trees in an old. crowded stand to the number in a normal, thinned stand. TABLE 6. Approximate number of trees of shortleaf pine to the acre in crowded and thinned stands. Total Number of Tkees per Acre Crowded Number which tan be Age of stand Unthinned removed from a previously stand Unthinned stand Years ' 20 1,950 1,250 980 25 1,440 970 675 :-!0 1,235 765 620 35 1,030 615 525 40 860 505 440 45 710 420 355 50 535 355 Maximum, Yield of Cordwood. — The maximum yield in cords is obtained earlier than the maximum yield in board feet. The best stands more than fifty years old give no heavier yield in cords than younger stands, because they have few trees to the acre, W'hile neglected stands in which disintegregation is taking place show even a decline in the volume. ^.f|; ; i W'-- I- ■t. I \i^' PLA.TE IV. A. crowded, large pole stand of shortleaf pine 40 years old, badly in need of thinning by removing the smaller pines and many of the hardwoods. Condition of larger trees, with long, smooth bodies, excellent. SHORTLEAF PINE IN VIRGINIA 25 TABLE 7. Yearly increment of shortleaf pine in cords {stem-wood and bark) of all trees three inches and over in diameter, hreasthigh. Unthinned Stands Thinned Stands Age Average Periodic Annual 1 Average Annual Periodic Annual of Annual Increment for each Increment in- Increment for each stand Increment 5 year Period cluding Thinnings 5-year Period Years Cords Cords Cords Cords 20 2.3 2.3 25 2.2 2. 2.3 2.2 30 2.1 ]. 2.3 2.0 35 1.9 .5 2.2 l.fi 40 1.7 .4 2. decrease 45 1.3 decrease 1.8 " 50 1.2 1.7 " 55 1.1 l.fi " 60 .8 " • I In both thinned and unthinned stands on average sites the maximum yield in cords per acre is obtained by cutting between ^he ages of twenty and twenty-five years, at whicli time a yield of fifty-seven cords per acre can be secured, or an average of 2.2 cords an acre a ye-AV. The size of the wood which is obtained at that time is, however, much smaller than that from older stands, and this fact aifects its value. 26 SHORTLEAF PINE IN VIRGINIA TABLE 8. Cost per cord of growing shortleaf pine cordwood, stemwood with bark, in unthinned and thinned stands; including thinnings, land value $5.00 an acre, interest rate five per cent, and one per cent yearly in addition for taxes and protection. Thinned Stands Accumulated U.NTHINNKD STATfDS ^ Age of stand Cost ot Land, at $5 per Acre, 6 per cent, in- terest, 1 p e r cent, added for taxes, less val- ue of land* Thinnings Net cost per Acre of pro- Final yield Final yield Cost of grow- ing per Amount Assumed value per Accu- mula- ted of grow- ing per cordt cord value! ducing Crop§ cord^'i Years Cords Cords Cords (1) (2) (3) (4) (5) (7) (8) (9) (10) 20 111.04 47 $.23 6.1 $ .10 $11.04 47 $.23 25 16 46 67 .28 5.1 .15 $ .78 J 5 68 62 .30 30 23 72 62 ..38 5.0 .20 1.97 21.75 67 .38 35 33.43 64 .52 4.8 .25 3.79 29.64 60 .49 40 46.43 65 .81 4.3 25 6.37 40.06 60 .66 45 63.82 64 .99 4.0 .25 9.60 54.33 59 .92 50 87.10 63 1.38 . 13.40 73 70 57 1..30 » Column 2 it obtained by calculating the Interest at 6 per cent, plus 1 per cent, for taxes, making a total of 6 per cent., compounded annually on a land value of 85 per acre. Since tue land will remain after the timber is sold, its value is not included in the cost oi growing. t Column 4 is obtained by dividing column 2 by column 3. I Column 7 Is the product of columns 5 and 6 compounded at 5 per cent every 5-year period. Th9 value of wood removed in thinnings (column 6) is only nominal on ac- count of its small size and the difficulty of making thlnnlngs- § Column 8 is the remainder after deducting column 7 from column 2. ij Column 10 Is obtained from dividing column 8 by column 9. Cost of Growincf Cordirood. — Table 8 .shows tlie cost of growing cordwood in both thinned and nnthinned stands at a five per cent, interest rate. PKODUCTION OF SAW TIMBER Influence of Densif}/ of Stand Upon Yield of /Saw Timber at Different Ages. Maximum yield in himber is obtained neither from stands which are continuously very crowded nor from understocked stands, but from stands which are periodically and lightly thinned after having been crowded. The most marked eftect of thinnings in crowded stands is m the amount and quality of the yield in board feet. The stands which were measured to determine the etfects of thinnings had been thinned in no definite manner; in some cases only the smaller trees, in other cases also some of the larger ones, had been cut out, SHORTLEAF PINE IN VIRGINIA 27 as farm needs required. Some of these thinned stands were evi- denth' somewhat understocked; some were still too crowded; •and others, at the time the measurements were made, had not had time to respond fully to the thinnings. It is probable that by sys- tematic thinningnlue of $5 an acre.* Age of stand Thinned Stand Value of stand neglecting Thinnings Gross rate per cent. Yielded on Land Value Per cent. Unthinned Stand Yield per Acre Value of stand Gross rate per cent. Yielded on Laud Value Pet cent. 30 8,-100 13,400 16,400 18,700 20,400 • $16.80 26.80 32.80 37.40 40.80 4.3 50 50 4.5 4.0 35 40 45 50 ' 6,000 10,200 13,100 $12.00 20.40 26.20 ■ 2.5 .3.2 3.8 TABLE 14. CORDWOOD STUMPAGE OF FINAL YIELD AT 25 CENTS A CORD. Gross rate per cent yielded by stands of shortleaf pine in old-field ivith a land value of $5 an acre* Thinned Stand —Unthinned Stand Age of stand Years Final yield Cords Total Value, per Acre, including Ac- cumulated Value of Thinnings at i% compound interest Gross rate per cent, Yielded on Land Value Per cent. Yield per Acre Cords Value of stand Gross rate .ver cent. Yielded on Land Value Per cent. 20 47 52 57 60 (iO 59 57 4!) 57 62 64 65 64 63 $11.75 14 25 15.50 16.00 16.25 16.00 15.75 4 3 25 30 35 40 45 50 118.74 16.08 18.44 19.65 23.94 26.43 4.0 4.0 3.8 3.6 3,5 3.2 4.2 3.8 3.5 3.0 28 2.5 Gross rate per cent, includes taxes and cost of protection as well as the interest on the Investment. 32 SHORTLEAF PINE IN VIRGINIA VALUE OF TREES AND STANDS The lumber from second-growth stands of shortleaf pine, when . awed into boards one inch thick and graded according to the rules of the North Carolina Pine Association, sells for a high- er price than if it is sold ungraded, 9r than if it is sold in the form of framing. The lumber which is sawed from young stands less than 35 years old is as a rule too narrow, and that from stands in which the trees have not been crowded, is too knotty to justify grading. TIiq older the stand the more valuable becomes the lum- ber which can be cut from it not only on account of greater widths but also a larger proportion of the high grade^. If the trees of ditt'erent diameters in a crowded stand which is about 50 years old (the age of maturity) are carefully sawed into boards of even width and uniform thickness, they will yield approximately the amounts of the different grades of lumber which are given in Table 15, The figures in this table are based on actual measure- ments of grades which were made at a mill where trees of these sizes and age were being cut. TABLE 15. Total volumes m bo'ird feet, and the amount of the f/rar/e.s- of luinher in trees of different diameters and heights in dense stands of short- leaf pine 4o to 60 years old. AMOUNT.S OF THB OlFFEKKNT Diameter Total height Feet Number of in foot logs Diameter Inside bark at the top Inches Grades S AWED From Trees Total volume breast- high Inches No. I. No. 2. B o No. 3. a r d Box or frm'g F e other grades e t 1-4 inch ^aw kerf Bd. ft. 7 48 li 5.0 4 12 6 22 8 m n 6.0 2 6 14 6 28 9 57 2 6.5 4 13 15 6 38 10 62 n 6.5 4 8 18 19 6 55 11 66 2h 6.5 8 12 25 28 6 79 13 70 3 7.0 18 23 27 35 6 l09 13 75 3 7.0 26 ' 33 37 40 6 142 14 78 3 7.5 32 1 38 48 56 7 J8I 15 SO 3i 7.5 47 40 63 67 9 228 16 80 H 8.0 70 48 75 /»i u 280 17 80 3^ 8.0 74 60 104 87 13 388 18 81 H 8.0 83 76 120 103 16 398 19 81 ^ 8.5 92 92 143 115. 18 460 20 81 3i 90 105 115 167 122 18 527 21 81 3i 9.0 120 133 197 125 18 598 22 81 3^ 9.0 136 163 230 129 20 678 The smaller trees in stands of this age are long-bodied and clear stemmed, have very little taper and thin bark, and, although Mature stand of sliortleaf pine. Trees nearly uniform in size and ready be cut for lumber. Groups of slender, wlndrtrm trees can be left for seed trees. SHOnXLEAl I'JXK FN VIR(;TNT.\ 33 the boards which can be sawed from such trees are narrow, they are comparatively free from knots and will justify grading if handled in connection with the wider boai-ds from the larger trees. Trees of the same size in younger stands are more tapering and more knotty, and the lumber is of lower grade. Air-dried lumber of the ditl'erent grades, consisting of mix- ed width, but less than 12 inches wide, is quoted (November, 1912) at the following prices per 1,000 board feet, delivered at Norfolk, Eichmond, Petersburg, Lynchburg, and Eoanoke: No. 1, $26; No. 2, $24; No. 3, $20; Box, $18; Red heart and cull, $16; Bark strip, Nos. 1 & 2, $20: Bark strip, box $12. In Table 16 these values have been applied to the amount of ditl'erent diameters delivered at Norfolk and the other points named above. TABLE 16. Value delivered at Norfolk, Rk-hmond, Petersburg Roanoke, and Lynchburg, of the graded lumber cut from trees of differerd diameters and heights* growing in crowded second-growth stands 45 to GO yearn old and the value of single trees and their stump- age per 1,000 board feet under different costs of sawing and delivery at ihtse points. Value of 1 umber de- Stumpage v alue per tree w ith expenses livered at Norfolk, Kich- of sawing and delivery per' Diameter mond, etc. 1,000 board ft. at breast-high From each tree Per 1,000 board ft. $10 U2 $14 7 $ .35 $16 95 $ .13 t $ .08 - $ .40 S .47 16.40 .18 .12 .06 9 .66 17.40 .28 1 .21 .13 10 1.01 1 8 35 .46 ! .35 .24 11 1 58 19.30 .74 .58 .42 12 2.16 19.80 1 .06 1 .85 .63 13 2.86 20.15 . 1.44 1.16 .87 14 3.79 20.95 1.98 1 1.62 1.26 15 4.75 21.40 2.58 I 2.12 1.67 If) 6.30 22.50 3.58 3.02 2.46 17 7.60 22.55 4.23 3.56 2.89 18 8.95 22 50 4 79 1 4.18 3.38 19 10.40 22.45 5.73 4.81 3.89 20 11.80 22.40 6.53 I 5 48 4.42 . 21 13.40 22.40 7.41 j 6.22 5.02 22 15.17 22.35 8.37 601 5.65 *Heighti which are given in table 15. tObtained by deductingthecost ofsawing and delivery per 1,000 board feet from the de- liverel value per 1,000 board feet, reducing the rtmaindSr to the value of one board foot and multiplying by the number of board feet per tree as shown In table 15: thus, $15.95 less SIOOO equal to .$6.95— ?5.i)o divided by IOjO and multiplied by 22 Is equal to S.13. In table 15 the expenses of saAving and delivery, $10; $12; and $14 per 1,000 board feet are supposed to represent a low, 34 SHORTLEAF IMXE IX VIR(;IMA a medium, and a high fo^,t of operation, and are made up of the cost of logging, felling, sawing, grading, interest on the investment and carrying charges, cost of selling, delivery at market and load- ing, drying, and profit of the operator. A profit of from $2 to $3 a thousand feet should be allowed in portable mill operations, the profit varying according to the size and length of the oper- ation. It is noteworthy that while the value of the lumber per 1.000 board feet which is yielded by trees of dilferent diameters increases rapidly up to IG inches in diameter, there is a decline in the value per 1,000 feet of the lumber which is sawed from trees of diameter above IT inches. This is due to the fact that the largest trees in these stands have larger and more numerous knots in their stems and yield a lower proportion of the high grades of lumber than do the slender, more clean stemmed, intermediate, and suppressed trees. If the number of trees of each diameter per acre in a 45- year old stand (see Table '2) be multiplied by the value per tree of each respective diameter, the sum of these amounts will give the total value of the stand per acre, and from this the value per 1.000 feet of the stand. A similar set of values can be determined for trees in younger and ohler stands. These are given in Table IT. TABLE 17. Value per 1,000 hoard feet of the lumber which can he sawed from dense unthinned stands of short-leaf pine nnder different costs of manufcmLure and delivery. Age of stand years Value per 1,000 board feet under a ofoperailon and delivery of cost $10 m 114 $ 5.40 6.00 7.05 8.60 10.05 4.00 5 05 6.60 8 05 $ 1 40 2.00 3.05 4.40 6.05 If the values in Table IT are compared with the cost per 1,000 board feet of growing timber, shown in Table 10, it will be seen that the investment, if the stand is unthinned. does not yield five per cent. net. except under a logging cost of $10 and when the stand is cut at the age of 50 years. In a regularly thinned stand from Avhich the very knotty trees have been systematically removed when the stand was young. SHOI{TLf:AF PrXE IX VTR(;IXIA :^r, Jeaving only the longest-bodied and clearest stemmed trees at each cutting and in which the trees have been forced to large diameters by isolation after the clear stemdeiigth is 50 feet in length, it is believed that the stiimpage value can be forced to a value of $8 a 1.000 feet under a logging cost of $12 wIhmi 50 years old. This would yield about $250 per acre. WASTE IX C'UTTIXt; SMALL TIJEES The following table shows the actual volume in board feet of trees of dilferent diameters anil heights when cut with a saw taking a kerf of one-fourth inch ; the volume in board feet when scaletl by Doyle-Scribner log rule; the volume of stem, wood only, in cubic feet: the number of boaixl feet. Doyle-Scribner rule, per cubic foot of volume; and the i)erccntage of waste. TABLE 18.. Volinnc in hoard feet and in cubic feet and. per cent of icaste in sawing trees of shortleaf pine of different diameters. Diame- ter Breast- high Total Height Actual Volume 1^ inch Saw Kerf Volume as scaled b\ Doyles Scribner rule Hoard feet Board feet '>•) s 28 Hi .'58 25 55 8s 79 56 109 SO 112 111 181 l:U '226 170 Volume of Stem Wood only Cubic feet Actual number of Board feet, per Cubic foot Per cent, of waste In Stump, Tv.ps, Slabs and Kerf 3. 75 H 75 ;>. 75 .S.3 72 4. m 4.5 62 4.9 59 5. 58 5. 58 The loss in scaling by Doyle-Scriber rule exceeds seventy-five per cent, of the total cul)ic volume of the stem until the tree reaches a diameter of thirteen inches, breasthigh. This large proportion of wa.ste is an excellent reason for not cutting young stands for saw timber or for not cutting the .-mall tree.> in old stands unless they are suppressed trees. LUMBEEIXtr AXD RESTOC KIX(i Simultaneously with lumbering coyies the subject of securing -I sec(md stand of young pine to iei)lace the one which is cut. 36 SHORTLEAP^ PINE IX VIRGINIA After ordinary culling, such as is practiced for farm use, or in clear cutting stands of pine for lumber or for fuel, hardwoods generally form the main part of the young stand. The reasons for this are explained under the heading "Permanency of Old- Field Pine Stands." To obtain reproduction of pine, it is neces- sary: (1) To cut nearly clean, that there may be abundant light: (2) To leave seed-bearing pine trees scattered over the area or standing nearby; (3) To cut out the large trees of such hard- woods as dogwood, post oak, hickory, persimmon, etc., which have sprung up beneath the pines, and Avhich would suppress many pine seedlings by their shade; (4) To bring as much of the min- eral soil to the surface as possible. The hardwoods should be cut in September, when their sprouting capacity is lowest. Two methods of cutting are suggested. One method, leaving isolated seed trees, is for use where the entire stand must be cut at one time. The other, cutting in strips, or groups, can be applied wdien there is a stead.y market for saw^ logs, as when there is a nearby permanent sawmill, or logs can be shipped to such a miH, and when it is possible to make two or more cuttings, not less than five years apart, in a stand, always having in view, hoAvever. the development of the valuable long-bodied and clean-stemmed trees (table 16) which are to form the mature stand. Isolated Seed Trees. — When the saw-timber must be remoA ed at one cutting it is advisable to prepare for the final cutting at the time of the last thinning by developing seed trees. At forty-five years of age, the production of seed by shortleaf pine is still ex- tremely light, particularly in dense stands. If there are no old forest pines which will serve for seed trees within 100 yai-ds of the tract, one object of the last thinning should be to select and develop trees for seed trees. Vigorous, large-croAvned trees should be selected for this pur- pose. They should be not less than four to the acre, and should be evenly distributed or else located on the tops of hills or knolls. Their crowns should be entirely freed by heavy thinnings on all sides. This should lead to the production of a heavy crop of cones and fertile seed within five years. If the crowns again crowd be- fore lumbering, they should again be freed by further thinning. When lumbering takes place, all merchantable trees should be cut except these seed trees, which should be able to produce enough seed in a few years to restock the land. (Plate V). If the seed trees are windfirm thev can i>o over until the next stand is cut: &7 RIIORTLEAJ^ PINE IN VIRGINIA if they fall, they ca.. be used without breaking down <""""";>' "/ he In trees in the young stand. Since the period of rest.ct in. by this method would probably occupy trom four to six years. tU soil would not be fully used dunng this time Cuttinf, in S««>.-Complete and rapid stocking .. bette as sured by cr.tting in strips, but this method presupposes a contmu ^rliket for saw logs. The area should be clear-cut over strip Z xceeding 200 feet in width, alternating with strips of equal r-dth whichlre only culled of the smaller trees. «" 1--^^,,^^ ^^ these strips should be at right angles to the roads; on '"Hy 1» d hy should lie up and down the slopes. The wooded strips shond be le-ily thinned by the removal of all except ^^ l^f-'";'- 'diich should not exceed twenty to the acre, and should be lef w i isdated. These trees will serve as seed trees, and on account If the" large number they should seed the entire area heavily wit*: five to ten years. As soon as a thorough restocking i assured they can be cut. Some of the young trees will be bioken dor brtthe loss will not te serious. The diameter gi-owth ot the seed trees after the thinning will be large because of this isola- ;; Blanks ten or more feet square left after the seed trees are cut should be planted by seed spotting as described under the di- re tons for planting. The two loggings will increase the danger from fire, requiring additional precautionary measures to be taken. This method can be varied by leaving the seed trees in groups. entti„ff Vnthmned ^«««A.-Both of the above methods pre^ suppose that the stand which is being cut has been thinned, and consequently is formed entirely or largely of trees of merchantable '"''ah understocked stand, similar to that shown in plate III, and in which the trees are largel.v of merchantable size can be cut so as to secure a restocking, by leaving some of the moie slender but well crowned trees for seed trees. The problem of cutting a crowded stand to the best advalUage and in a manner to secure a restocking is more difficult. The tiees n such a stand have a much greater range of diameter than thos in a thinned stand. There is a large number of small suppressed and intermediate trees which may be too small to be c« eco- nomically for saw timber '(see "Waste in cutting small rees" page 35) In such a case it may be desirable to remove the stand n two or more cuttings, made at intervals of five or more .v«ar«- At the first cutting only the largest trees should be cut, particulariy 38 SHORTLEAF PIXE IX VIR(;IXIA those which have short and knotty stems. Such as have very slender clean stems and good crowns should be left, but enough of the largest trees should be taken to open the crown cover one- third. Such a cutting might remove one-tenth of the total num- ber of trees but more than one-half of the saw log volume of the stand. At the second cutting not only should most of the trees which have grown to merchantable size l)e removed, but also such of the smaller stunted trees as have shown no indication of thrift since the first cutting. The trees wliich are left should be choice clean-stemmed specimens with medium sized, but thrifty crowns. They can be left at the rate of ten to twenty to the acre. Such trees as have weak stems which would be likely to be bowed or broken by wind or sleet should not be left. Thickets of high shrubs and broadleaf trees should be cut. It is probable that by the time of the second cutting groups of young seedlings, about one foot in height, will have api)eared beneath the openings made by the first cutting. Seed from the trees which are left after the second cutting will complete the restocking. Two courses can be followed in regard to the trees which are left after the second cutting. Either they can be removed after thorough seedling es- tablishment is assured, or they can be held over an-d cut at some thinning period of the young stand. If trees with fifty feet of clear length and diameters of from ten to twelve inches are left after the second cutting and are held until they are tAventy to twenty-four inches in diameter their stumpage value Avill increase from three to five times. This increase in value will be due en- tirely to the greater size of the bigs, which Avill yield a high grade of lumber and can be sawn with small waste. (See Tables Ifi and 18 and Plate II, Fig. 1). No method of cutting a crowded unthinned stand, howcAer. will give as great a yield in board feet per acre, or will produce logs of as high a gi'ade. as can be obtained from a well-thinned stand. PLAXTINO AVASTE LAND On many farms in middle Virginia there are tracts of gMllied. or shallow soiled or rocky, or other poor or waste land which are either without a growth of pine or are stocking extremely sloAvly and irregularly. Shortleaf pine could be planted profitably on such tracts. The sound seed of this pine sprout so freely, and the growth of the young seedling is so rapid, that direct seeding can SIIOKTI.KAI PINE IN \IHGINIA. 39 be made in place of usiiio- young phuits. Seed should be planted in spots six feet apart in well loosened soil and lightly covered, not deeper than one-half inch Avith earth. One of the two follow- ing methods can be used. If the tract can be plowed, shallow furrows can be laid otl' at intervals of six feet with a shovel plow or small turning plow, and the seed dropped at six-foot intervals m the furrows and lightly covered with a weeding hoe. If a plow cannot be used, the earth can be loosened with a light grub hoe over a spot six or eight inches sijuare, and the seed planted and lightly covered in the middle of this spot. If the soil is either (b-y or light and sandy the planter should step ou the spot after covering to bring the earth in <'lose contact with the seed and in- sure germination. Set poles should be used to keep the rows straight. The seed of shortleaf piue has a low germinating percentage, seldom more than forty-five per cent., and a number of seed, twelve or fifteen, should therefore be dropped in a hole. As many as can easily be held between the thumb, index finger and second hnger will insure a stand. There are about 50,000 seed to a pound, so that a pound, if carefully handled, will plant an acre. The smallness of the seeds, however, makes them difhcult to handle, and an inexperienced planter will usually drop more than are necessary for obtaining a stand. Planting should be done at any time between the middle of February and the first of April, whenever the soil is in suitable condition. Protection from fire and cattle is absolutely necessary until the trees are three or four inches in diameter and the bark thick enough to afford reasonable protection, which will require from ten to fifteen years. Heturns from Plantations. — If such plantations are carefully thinned their yield should greatly exceed that of natural stands. rhe cost of planting au acre and of carrying the investment is calculated on the basis of a land value of %l() an acre, Avith five per cent, compound interest, which includes an allowance of one per cent, an acre a year for taxes and protection. This land value is low for soils which will produce good shortleaf pine. The prices at which stumpage must be sold to net four per cent, on the in- vestment are shown in Table 10. Cost of land $10 00 Cost of seed one pound per acre 2 50 Cost of planting per acre 1 50 Total initial cost of investment $14 00 40 gHOUTLEAF PINE IN VIRGINIA. TABLE 19. cost of producim snortleaf pine stumpage in plantations with five per cent gross interest on investment. Thinnings made at middle of decades yield about eleven cords at twenty-five years, fifteen cords at thirty-five years, and ten cords at forty-five years per acre. The minimum cost of producing lumber would be about i^3.8-^ per 1,000 board feet, when a stand is about forty years old. The minimum cost of producing cordwood would be about sixty-five cents a cord at an age of thirty years These figures, wnich are conservative, indicate that planta- tions can be expected to yield at least five per cent, gross or our per cent, net after allowing one per cent, or ten cents an acie a year, for taxes and protection. With regularly made and care^ fullv executed thinnin-s, the yield would probably exceed that ot the irregularly thinned stands on which the calculations are based and the cost of production would be lowered; m other words a higher interest rate would be obtained. In order for a plantation to yield five per cent, net or six per cent, gross, allowing one per cent, an acre a year for taxes and fire protection, the following returns, which are fair and reasonable, must be obtained from stands of dilferent ages. SHOR'nj^AF PINE IK VIR(ilNIA. 41 TABLE 20. Cost of produciniii shortlraf pmc stumpage in plantations with six per cent gross interest on investment. w^Boa innings ladle of 50 cents landing iiulated t 4 per ard feet 9" and lameter h. 4-> J, 'O^fe o% 1 £.2 8h 5^- o •< Accui ofIn Acre poun cent Valu ^liSa*^ l^si it «^ts *^s Years sap. -.5 2 r:oSS l°°« s^ 20 $ 34.80 21 11.66 30 70.36 $ 7.00 5,8C0 $ 10.91 51 1.23 40 184.06 20.10 14,800 7.70 60 1.88 50 247.88 40. 2S 19,300 10.77 60 3.30 * On account of the small amount of the thinnings and the short period during which tha money from them would be invested only 4 per cent, net is allowed on them. In neitlier of the foregoing calculations is any allowance made for superintendence, and possible losses from insects, sleet and snow breakage, and windstorm damage, but it must also be re- membered that the constant increase in the price of timber is like- wise neglected. thp: protpxtion' op^ stands The two important dangers to pine stands, fire and insects, are in a measure interrelated. Those trees Avhich have been weak- ened or injured by fires invite insects, while stands which are lit- tered by the wood which has died from in.sect depredations, and which have become grassy on acconnt of openings made in the crown cover where trees have been killed by insects are particularly expo.sed to serious damage from fire. With both dangers, pre- vention is the most effective means of control. Fires. — While the danger of fire is always present, it is far more serious in connection with young stands and particularly those in jjrocess of stocking, such as fields which have recently been turned out, or newly cut or lumbered land. Fires injure such yonng stands at any season of the year in which the}' may occur. Although many individuals of shortleaf pine between one and two feet high, when killed by an early spring fire, will sprout.. the sprouting capacitv is irregular and unreliable (Plate VI, fig. 2). Moreover, most of such sprouts die in a few years, while many of the survivors are forked. After the tenth vear. the heavv shade of 42 SHORTLEAF PINE IN VIRGINIA, croAvded stands and the thickened bark greatl}' reduce the danger of fire, but even the heavy bark of old trees does not afi'ord com- plete protection from hot spring fires when these are driven by a strong vpind. Thickly stocked shortleaf pine stands do not, as a rule, become grassy or foul with shrubs and herbage, and conse- quently do not require periodic winter burning for the purpose of protection, such as may often be necessary for pole stands and mature stands of loblolly and longleaf pines. Although no visible damage may be done to older trees by such burnings, the rate of growth is reduced by the destruction of the pine straw and the humus, while even the slight scorching of trees may lead to the entrance of insects or fungi. Young stands and areas which are in process of stocking are most effectively protected from fire by establishing and maintain- ing open fire lanes, free from straw and litter, completely around them or "on the exposed sides. A shallow furrow can be plowed every year on both sides of the lanes, and the intervening strip can be raked clear, or it can be burned during damp, quiet weather. In older stands the straw and litter can be raked off the lanes each autumn and used for stable beddings. Well established lanes, if they are free from stumps and shrubs, may conveniently be raked with a side delivery rake. By locating lanes at intervals through a large tract, as well as around it, it is separated into blocks whicli are individually protected. Where possible, roads and paths should be used for lanes. Since there is great danger of a serious lire during and immediately after lumbering, extra protective pre- caution should be taken at that time. A fire that occurs at that time will frequently destroy the pine seedlings, but the replace- ment of the hardwoods and shrubs takes place at once by sprout- ing. Repeated fires eliminate the pines. When timber is sold or when logging is done by contract, an enforceable fire penalty clause should be inserted in the contract, in order to obtain the necessary protection. The Federal Government under the terms of section 2 of the Weeks Law extends its co-operation to States in assisting them to protect the forested water-sheds of navigable streams from fire. In order to secure assistance of this kind a State must have provided by law for a system of forest fire protection and must have appropriated funds for the purpose. Scarcely a more im- portant step could be taken by the State of Virginia towards the conservation of its forests than the establishment of a fire pro- SHORTLEAF PINE IN VIRGINIA. 43 lectivf system. The readiness of the Federal Government to chj- operate under the terms of this hiw as soon as the State itself makes a start is an incentive to immediate action. In the short- leaf pine area of ^"irginia the water-sheds of the Appomattox, James, Roanoke and Eapidan rivers coulil he protected hy such co-operation. Ins-ects.—The diinger of fire is greatest to seedling stands, hut the possibility of insect damage, although it is always present, increases after the trees are twenty years old. One of the most [)ernicious insects is the pine bark beetle, Dendr act onus frontalis, Zimnj which devastated the coniferous forest of middle and w^est- ern Virginia between 1888 and 1892. This species channels the inner bark in the middle part of the stem and eventually girdles the trees, thus killing tliem. Other beetles infest the wood of the living tree, and yet others attack only dead or dying trees. The fecundity of the pine bark beetle is so great that several large broods are produced in a single summer, and when conditions are favorable they propagate in enormous numbers and cause serious depredations. Pure stands in old fields invite destructive attacks, since in them the insects can readily spread from tree to tree. The best way to hold this insect in check is to keep the trees ill thrifty condition by preventing overcrowding, by removing wood which would serve as breeding places, and by cutting out in- fested trees. It is particularly desirable to maive these protective cuttings before the spring and early summer broods of the insects come out and spread. Infested trees should be promptly removed as soon as noticed. The removal of weak trees in thinning elimi- nates them as sources of breeding, while cutting low stumps and close utilization, or the piling and burning of tops — operations which are sometimes advisable for other reasons — remove much other wood. The cutting of live trees should be limited as far as possible to the winter, but dead trees can be cut at any time. Special care should be used in summer cutting not to leave freshly- cut tops touching live trees, and to remove promptly trees that have been killed by lightning. When cordwood or logs which are spring or summer cut cannot be promptly removed, they should be peeled or racked in the sun, that they may dry. Detailed infor- mation in regard to protection against this beetle is contained in Farmers' Bulletin, No. 476. Fungus Diseases. — The most important known fungus which attacks shortleaf pine is Tramefes pini, the cause of redheart. 44 SHORTLEAF PINE IN VIRGINIA. This is a darlc brown siiutf-colored "punk'' which gains entrance into the heartwood of the upper part of the stem through knot holes, and into the lower part by wounds caused by falling trees, fire scars, (Plate VI, fig. 2), and insects. Trees which show the "punk" should be promptly cut. Pine stands are also exposed to damage from windstorms, and from sleet and wet snow. The damage by wind cannot be pre- vented. Fortunately, shortleaf pine, when it grows on deep soils, is anchored by a long, strong taproot, and is very windfirm. On shallow soils, particularly a hard-pan near the surface which checks the descent of the taproot, it windfalls badly. Slender trees are occasionally bent or even broken by wind. Frequent light thin- nings render the trees in such stands more windfirm. Sleet and wet snow are dangers against which there is no ade- quate protection. The weight of sleet and wet snow frequently breaks the leaders, and in crowded stands may bend many stems beyond recovery, break them, or even uproot them. The only pre- cautionary measure is to strengthen the resisting power of limbs and stems by thinning. Trees in young stands less than twenty years old are the most likely to be broken and bent, while trees in older stands, in which isolation is taking place, are the most apt to be overturned. P'requently. insect depredations follow this kind of damage. '^^Si N PLATE VI. A culled stand of mixed pine and hardwoods. The defecUve o^J^ '^ ^he left foreground Is partially shading groups of thrifty Pj-^ seed ings and sbo d be removed. The large pines in the background serve as seed trees. The seed-lngs are greatly exposed to tire.