Effects of Fertilization and Thinning on Heartwood Area, Sapwood Area and Growth in Scots Pine (original) (raw)
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Within-tree variation of heartwood and ring width in maritime pine (Pinus pinaster Ait.)
Forest Ecology and Management, 2005
The development of heartwood and sapwood in maritime pine (Pinus pinaster Ait.) in relation with tree and cambial age and growth rate was studied in ten trees randomly sampled at harvest (54-85-year-old) in a commercial stand in central Portugal. Average ring width at stem base was 1.84 AE 0.34 mm for 50 years of age. Growth rate decreased with cambial age and for the same cambial age increased along the stem with tree height. The number of heartwood rings was strongly correlated with cambial age. Heartwood formation was estimated to start at approximately 21 years of age and to proceed at a constant annual rate that increased with age (0.5 and 0.7 rings year À1 below and above 50 years of age). Within the tree, heartwood decreased with stem height, but in the lower part of the stem two patterns of variation were shown: a continuous decrease or an increase from stem base to a maximum at 2-3 m and a decrease afterwards. Sapwood radial width remained approximately constant within the tree and correlated positively with tree growth.
Annals of Botany, 2001
As the proportion of sapwood (SW) transformed into heartwood (HW) is irregular both radially and longitudinally in trunks of Maritime pine (Pinus pinaster Ait.), it has been suggested that HW formation is a developmental process, regulated internally within the tree. In trees where stem growth is eccentric due to stem lean or wind action, the number of annual growth rings of SW transformed into HW is greater on the compressed side of the tree. To determine the contribution to bending stiness, if any, of this prematurely formed HW, four point bending tests were carried out on fresh HW and SW samples taken from the same growth ring, or neighbouring growth rings, at dierent cross-sectional positions at a height of 2 m from six 52-year-old Maritime pines. The mean (+s.e.) modulus of elasticity (E) was 7. 6 + 0. 3 GPa (longitudinal direction) for all samples. No signi®cant dierences in E were found between HW and SW; thus HW does not play a signi®cant mechanical role in bending stiness. To test a second hypothesis that early HW formation on the compressed side of trees may maintain a constant, optimal volume of SW around the tree, the Pipe Model Theory was applied to 12 52-year-old leaning Maritime pines (angle of lean varied from 0±228). The surface area (S) of the SW was determined at dierent heights up the trunk and correlated with crown surface area (S crown). Regressions between S SW and S crown were highly signi®cant, thereby supporting the theory that HW formation and extension is controlled internally in Maritime pine. HW formation in Maritime pine then serves to maintain an optimal proportion of functional SW which is an important criterion for survival in a species often subjected to severe drought for long periods.
Vertical heartwood variation patterns and prediction of heartwood volume in Pinus canariensis Sm
Forest Ecology and Management, 2003
Heartwood and sapwood distribution along the stem were assayed in 26 Canary Island pines growing along the natural range of the species at the Canary Archipelago. Trees were sampled at breast height and approximately every 2 m up to the lowest section without heartwood. Heartwood and sapwood thickness, together with age and radial growth traits were measured in each section. Heartwood tapered towards the top of the tree and disappeared at a certain height. Sapwood distribution was more variable among individuals; sapwood width was almost constant in some individuals but tapered slightly or with a curvilinear variation in others. Two general patterns of heartwood and sapwood variation were defined, one characterised by a constant decrease in heartwood percentage and subsequently a slight sapwood variation along the stem (uniform pattern) and another one with a peak in heartwood percentage at a height between 4 and 8 m (irregular pattern). The relative crown height to total tree height was significantly higher in the second group, averaging 49% versus 32% in the uniform group. A mechanical-physiological hypothesis is given to explain this result in the light of similar results in other species. A model including heartwood radius at breast and tree height as predicting variables was able to explain 90% of heartwood radius at a given height in the stem. A similar model with sapwood width at breast height explained 80% of sapwood width variation along the stem. Heartwood volume was predicted by means of log-linear regression models including heartwood diameter at breast height and tree height ðr 2 ¼ 97:5%Þ. Sapwood volume was better predicted through stem diameter at breast height and tree height ðr 2 ¼ 92:7%Þ. #
Coincident variations in growth rate and heartwood extractive concentration in Douglas-fir
Forest Ecology and Management, 2003
Extractives can have a major impact on the properties of heartwood; however, our understanding of the process of heartwood formation and extractives production is limited and there are few data on how environment affects heartwood extractive content. This study assessed the relationship between growth ring width and extractive content of heartwood in Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) trees. The radial growth rates of the sampled trees were variable over their 53-61 years, in part, because of recent stand thinning treatment. The year that each heartwood increment was formed was estimated by assuming that the trees maintained the same number of growth rings of sapwood in the past as they had at the time of sampling. Growth ring width increased after the recent thinning and there was an associated increase in the extractive content of the heartwood estimated to have been formed at the same time. In addition, there appeared to be a rough correlation between growth ring width and extractive content in the time before the thinning. These results suggest that silvicultural treatments that affect growth rate may affect wood durability in Douglas-fir. #
Heartwood in relation to age and growth rate in Pinus sylvestris L. in Scandinavia
Forestry, 2003
Softwood timber is an excellent material for a variety of applications. As far back as the fourth millennium BC, King Gilgamesh of Uruk decided that timber from old trees was the best material for the construction of his palace: 'I selected. .. until I had found a fully mature pine' (Dalley, 1991). Traditionally, mature pine has been associated with heartwood. Pine heartwood and pine sapwood can, in several respects, be considered two different timber products. In comparison to heartwood, sapwood possesses an open wood structure, which is penetrable to moisture, solvents and air, and is vulnerable to biological degradation. Sapwood is light in colour and is easily painted, impregnated or otherwise treated. Heartwood, on the other hand, may be used to obtain timber less disposed to moisture fluctuations and, hence, more
2008
The study presents radial and axial variation in the proportions of sapwood and heartwood in stems of common oak growing under varied growth conditions. Collected material was analyzed in order to find factors affecting irregularity in sapwood and heartwood zones in stems of trees representing investigated populations. The proportion of sapwood and heartwood in the stem and the rate of heartwood formation are influenced by crown size and transpiration efficiency of trees, social class of tree position as well as site conditions. The proportions of sapwood and heartwood vary also between age classes of trees. A considerable effect on the width of the sapwood zone in trees was found for crown size. In this case correlations were positive in both analyzed age classes, although in age class III they were weaker than in age class IV.
Xylem anatomical traits related to resinous heartwood formation in Pinus canariensis Sm
Trees, 1998
AbstractmResinous heartwood (lightwood) is an important feature in Pinus canariensis (Canary Island pine), as this wood has very good mechanical and aesthetic characteristics. In order to determine anatomical traits related to lightwood formation, structure of axial resin canals, xylem cell connections and cell contents were studied on wood samples from sites with different environments. Specimens consisted of radial wood cores and stem discs at breast height. The unknown presence of a wide parenchymatous sheath in axial resin canals is highlighted, and a general description of this formation is provided. Quantitative anatomical traits were examined to explain deviations of heartwood radius from the values predicted by a regression model. Thus, percentage of rays and axial parenchyma were assayed in ten individuals. Those with a larger heartwood than predicted by their age and growth tend to display a higher percentage of axial parenchyma in the inner xylem (5th growth ring). More than 40% of heartwood9s dry weight is due to extractives, mainly resin, fats and phenolic compounds, ranging up to 4% in sapwood. This intense soaking is explained by the high proportion of living cells in the xylem, and their capability to accumulate large quantities of reserve starch. These traits are closely linked to other important features of the species, such as stem sprouting and resistance to extreme wounding.
82 New Zealand Journal of Forestry Science 17(1
1982
A stem and branch growth model, TreeBLOSSIM, has been developed for Pinus radiata D. Don that predicts the location and diameter of branches adjacent to the stem on an annual basis. Research is under way to extend the model to predict wood properties in three dimensions: vertically with increasing tree height, radially with increasing tree age, and circumferentially around a growth ring. Four studies were carried out to examine the role that branches may have in influencing the 3-dimensional variability of wood properties. These studies illustrated how wood fibres were arranged in the vicinity of a branch, and how the stem cross-sectional shape varied through a cluster of branches; and they indicated that the wood properties in the internode below a branch cluster may be influenced by the diameter of the branches.