LIGNUM: A Tree Model Based on Simple Structural Units

The model LIGNUM treats a tree as a collection of a large numberof simple units which correspond to the organs of the tree.The model describes the three dimensional structure of the treecrown and defines the growth in terms of the metabolism takingplace in these units. The activities of physiological processescan be explicitly related to the tree structures in which theyare taking place. The time step is 1 year. The crown of the model tree consists of tree segments, branchingpoints and buds. Each pair of tree segments is separated bya branching point. The buds produce new tree segments, branchingpoints and buds. The tree segments contain wood, bark and foliage.A model tree consisting of simple elements translates convenientlyto a list structure: the computer program implementing LIGNUMtreats the tree as a collection of lists. The annual growth of the tree is driven by available photosyntheticproducts after respiration losses are accounted for. The photosyntheticrate of foliage depends on the amount of light. The amount ofphotosynthates allocated to the growth of new tree segmentsis controlled by the light conditions and the amount of foliageon the mother tree segment. In principle, the biomass relationshipsof the tree parts follow the pipe model hypothesis. The orientationof new tree segments results from the application of constantbranching angles. LIGNUM has been parametrized for young Scotspine (Pinus sylvestrisL.) trees. However, the model is generic;with a change of parameter values and minor modifications itcan be applied to other species as well. Growth model; object-oriented modelling; tree architecture; branching structure; Pinus sylvestrisL.; developmental morphology and physiology; photosynthesis; respiration     

HETEROPHYLLY AND NEOFORMATION OF LEAVES IN SUGAR MAPLE (ACER SACCHARUM)

Variation in leaf form and timing of leaf initiation were investigated in vigorous leader shoots of open-grown saplings and larger forest trees of sugar maple (Acer saccharum Marsh.). Winter buds of leader shoots usually contained 6 or 8 leaf primordia and embryonic leaves, whereas 12 to 18 leaves typically expanded along the shoots each year. Preformed (early) leaves differ in form from neoformed (late) leaves. As in some other Acer species, the first-formed late leaves have large angles of secondary lobe divergence and deeply indented sinuses. This pattern of heterophylly contributes to the multilayered nature of open-grown saplings and leader shoots of forest trees of sugar maple.     

Patterns of tree replacement: canopy effects on understory pattern in hemlock-northern hardwood forests

The effect of canopy trees on understory seedling and sapling distribution is examined in near-climax hemlock-northern hardwood forests in order to predict tree replacement patterns and assess compositional stability. Canopy trees and saplings were mapped in 65 0.1-ha plots in 16 tracts of old-growth forests dominated by Tsuga canadensis, Acer saccharum, Fagus grandifolia, Tilia americana, and Betula lutea in the northeastern United States. Seedlings were tallied in sub-plots. Canopy influence on individual saplings and sub-plots was calculated, using several indices for canopy species individually and in total. For each species sapling and seedling distributions were compared to those distributions expected if saplings were located independently of canopy influence. Non-random distributions indicated that sapling and seedling establishment or mortality were related to the species of nearby canopy trees. Hemlock canopy trees discriminate against beech and maple saplings while sugar maple canopy favors beech saplings relative to other species. Basswood canopy discourages growth of saplings of other species, but produces basal sprouts. Yellow birch saplings were rarely seen beneath intact canopy. Since trees in these forests are usually replaced by suppressed seedlings or saplings, canopy-understory interactions should influence replacement probabilities and, ultimately, stand composition. I suggest that hemlock and basswood tend to be self-replacing, maple and beech tend to replace each other, and birch survives as a fugitive by occupying occasional suitable gaps. This suggests that these species may co-exist within stands for long periods with little likelihood of successional elimination of any species. There is some suggestion of geographical variation in these patterns.     

Differential drought responses between saplings and adult trees in four co-occurring species of New England

Tree-ring characteristics in four species were examined to address whether co-occurring mature trees of different successional status respond differently to drought, and whether saplings of these species have a greater response to drought than mature trees. We examined saplings and mature trees of paper birch, yellow birch, red maple and sugar maple, which varied in successional status (shade-tolerance) and co-occurred at Harvard Forest, Petersham, Mass., USA. Three drought events in 1964–1966, 1981 and 1995 were identified using climate data. For mature trees, there was no significant interspecific difference in relative changes in ring-width index (RWI) during the 1964–1966 and 1995 drought events. However, the interspecific difference was significant in the 1981 drought event. Response function analysis for mature trees showed that the radial growth of sugar maple was mainly controlled by spring and summer precipitation, red maple by spring and summer precipitation and temperature, yellow birch by winter and summer precipitation, and spring and summer temperature, and paper birch by spring and summer precipitation and spring temperature. Saplings of sugar maple and yellow birch, but not red maple and paper birch, showed significant positive correlations between RWI and annual total precipitation. In the 1995 drought event, saplings and mature trees of red maple and paper birch differed significantly in drought responses, but this was not true in sugar maple and yellow birch. Our results do not support a generally greater response in saplings than in mature trees, nor an early- versus late successional difference in drought responses.     

The role of forest tent caterpillar defoliations and partial harvest in the decline and death of sugar maple

Background and Aims

Natural and anthropogenic disturbances can act as stresses on tree vigour. According to Manion''s conceptual model of tree disease, the initial vigour of trees decreases as a result of predisposing factors that render these trees more vulnerable to severe inciting stresses, stresses that can then cause final vigour decline and subsequent tree death. This tree disease model was tested in sugar maple (Acer saccharum) by assessing the roles of natural and anthropogenic disturbances in tree decline and death.

Methods

Radial growth data from 377 sugar maple trees that had undergone both defoliations by insects and partial harvest were used to estimate longitudinal survival probabilities as a proxy for tree vigour. Radial growth rates and survival probabilities were compared among trees subjected to different levels of above- and below-ground disturbances, between periods of defoliation and harvest, and between live and dead trees.

Key Results

Manion''s tree disease model correctly accounts for vigour decline and tree death in sugar maple; tree growth and vigour were negatively affected by a first defoliation, predisposing these trees to death later during the study period due to a second insect outbreak that initiated a final vigour decline. This decline was accelerated by the partial harvest disturbance in 1993. Even the most severe anthropogenic disturbances from partial harvest did not cause, unlike insect defoliation, any growth or vigour declines in live sugar maple.

Conclusions

Natural disturbances acted as predisposing and inciting stresses in tree sugar maple decline and death. Anthropogenic disturbances from a partial harvest at worst accelerated a decline in trees that were already weakened by predisposing and inciting stresses (i.e. repeated insect defoliations). Favourable climatic conditions just before and after the partial harvest may have alleviated possible negative effects on growth resulting from harvesting.Key words: Manion, tree disease model, disturbance, Acer saccharum, tree mortality, tree vigour     

Light and tree size influence belowground development in yellow birch and sugar maple

The effects of light and tree size on the root architecture and mycorrhiza of yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh) growing in the understory of deciduous forests in southern Québec, Canada were studied. At the study site, small (<50 m²), medium (101–200 m²) and large (201–500 m²) canopy gaps were investigated. From within these gaps, 17 yellow birch and 23 sugar maple saplings from 40 to 600 cm in height were sampled. In both species, root biomass and morphological traits were strongly correlated with tree size, but only weakly with light availability. Increased root biomass was primarily allocated to coarse roots and secondarily to fine roots. Yellow birch roots were longer, had a larger area, more endings and branches and grew more rapidly than sugar maple roots. Mycorrhizal colonization increased with available light and declined with tree age in sugar maple and was positively associated with tree size in yellow birch. The study demonstrates that tree size is a very important determinant of how belowground systems acclimate to understory conditions.     

Lorentzian model of roots for understory yellow birch and sugar maple saplings

Total 66 small (<50m(2)), 24 medium (101-200m(2)) and 36 large (201-500m(2)) canopy gaps at the three sites of yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh) forests were established in southern Québec, Canada. Half of the gaps were covered by 8x8m(2) shading cloths to mimic a closed canopy. From these gaps, 46 understory yellow birch and 46 sugar maple saplings with different tree ages and sizes were sampled. Single- and multi-variable linear and nonlinear models of root biomass and traits (root surface area, volume, length and endings) were developed and examined. Lorentzian model as a multi-variable nonlinear model was firstly applied to the simulations using both base diameter and height, and performed the best fit to total root biomass in both species with the highest correlation coefficients (R(2)=0.96 and 0.98) and smallest root mean squared deviations (RMSD=7.85 and 7.02) among all the examined models. The model also accurately simulated small fine root (2.0mm in diameter), coarse fine root (>2.0-5.0mm) and coarse root (>5.0mm) biomass (R(2)=0.87-0.99; RMSD=2.24-6.41), and the root traits (R(2)=0.71-0.99; RMSD=0.19-19.38). The study showed yellow birch roots were longer, larger, had more endings (tips) and grew faster than sugar maple roots. The root traits were largely distributed to small fine roots, sharply decreased from small fine roots to coarse fine roots, the fewest in coarse roots except for root volume. When trees were large, coarse root biomass increased more rapidly than fine root biomass, but vise versa when the trees were small.     

Phenolic Growth Inhibitors Isolated from Dormant Buds of Sugar Maple (Acer saccharum Marsh)

Phenolic growth-inhibiting substances were isolated from dormantbuds of sugar maple (Acer saccharurn Marsh) by paper chromatographyof their aqueous methanolic extracts. Inhibition was determinedin germination bioassays using lettuce (Lactuca sativa var.Grand Rapids) seeds. An inhibition of some 20% was attributedto four major phenolics identified as ferulic, vanillic, p-coumaric,and caffeic acids. Quercetm was also present and caused a weakstimulation of growth. Fractionation of the extract with acidic, neutral, and basicgroups indicated that more phenolic compounds were in the acidicgroup than in the neutral, while none were in the basic group. On a seasonal basis, autumn buds had a higher phenolic contentthan winter and spring buds. The results presented are not inconsistentwith the view that growth-inhibitory phenolic compounds couldcontribute to dormancy in sugar maple buds.     

A gall-inducing arthropod drives declines in canopy tree photosynthesis

Mature forest canopies sustain an enormous diversity of herbivorous arthropods; however, with the exception of species that exhibit large-scale outbreaks, canopy arthropods are thought to have relatively little influence on overall forest productivity. Diminutive gall-inducing mites (Acari; Eriophyoidae) are ubiquitous in forest canopies and are almost always highly host specific, but despite their pervasive occurrence, the impacts of these obligate parasites on canopy physiology have not been examined. We have documented large declines in photosynthetic capacity (approx. 60%) and stomatal conductance (approx. 50%) in canopy leaves of mature sugar maple (Acer saccharum) trees frequently galled by the maple spindle gall mite Vasates aceriscrumena. Remarkably, such large impacts occurred at very low levels of galling, with the presence of only a few galls (occupying approx. 1% of leaf area) compromising gas-exchange across the entire leaf. In contrast to these extreme impacts on the leaves of adult trees, galls had no detectible effect on the gas-exchange of maple saplings, implying large ontogenetic differences in host tolerance to mite galling. We also found a significant negative correlation between canopy tree radial increment growth and levels of mite galling. Increased galling levels and higher physiological susceptibility in older canopy trees thus suggest that gall-inducing mites may be major drivers of “age-dependent” reductions in the physiological performance and growth of older trees.     

Recruitment Processes and Species Coexistence in a Sub-boreal Forest in Northern Japan

We investigated the recruitment of saplings (across the 2 m-heightthreshold) of six species,Picea jezoensis, Abies sachalinensis,Betula ermanii, Picea glehnii, Acer ukurunduense andSorbus commixta,in a sub-boreal forest, northern Japan. Data were collectedin a 2.48-ha plot over six growing seasons (1989–1994).We used path analysis to analyse the relationships between therecruitment rates of saplings and the stand structural attributessuch as mother tree abundance, stand crowdedness, stand stratification,Sasabamboo density on the forest floor, and fallen log abundance.The combination of stand structural attributes affecting recruitmentrates of the six sub-boreal forest tree species differed markedlyamong the species and corresponded to species composition. Itis suggested that the size-structure dynamics of adult treesof the sub-boreal forest are regulated largely by differentregeneration processes among the species and only slightly byinterspecific competition between adult trees because interspecificcompetition between adult trees was not evident. The dynamicsof species coexistence of the sub-boreal forest should be describedas a process combining the diversity of recruitment processesof saplings of the component species and the diversity of interspecificcompetition between adult trees. We propose the boundary conditionhypothesis for species coexistence in the sub-boreal forest,that the persistence of each component species is ascribed largelyto the different recruitment processes of saplings (boundaryconditions for adult tree growth dynamics) and only a littleto interspecific adult tree competition. Climax forest; safe site; regeneration niche; mode of competition; species diversity     

VARIATION OF SHOOT MORPHOLOGY AND BIFURCATION RATIO IN SUGAR MAPLE (ACER SACCHARUM) SAPLINGS

Open-grown sugar maple saplings differ qualitatively in their gross morphology when compared with saplings growing in shaded forest understories. Forest-grown saplings have their leaves distributed in a few planar layers, while open-grown saplings exhibit fuller crowns and more profuse branching. In order to quantify these observed differences in branching patterns, ordering methods were applied to twenty saplings each from forest and open sites. Bifurcation ratio, an index of branching previously assumed to be species constant, differed significantly between forest-grown and open-grown saplings. Bifurcation ratios for forest-grown saplings were low, with a mean of 3.19. Values for open-grown saplings were generally higher, with a mean of 7.05. This variation of bifurcation ratio between forest-grown and open-grown sugar maple saplings is the first such variation within any species to be reported. In addition, open-grown saplings were characterized by more extension growth of terminal shoots than forest-grown saplings. These results suggest that sugar maple has a range of branching and light interception characteristics that suit it well in different microenvironments.     

Diversity of canopy and understorey spiders in north-temperate hardwood forests

1 We characterized and compared diversity patterns of canopy and understorey spiders (Arachnida: Araneae) on sugar maple ( Acer saccharum Marsh.) and American beech ( Fagus grandifolia Ehrh.) in hardwood forests of southern Québec, Canada.
2 We sampled canopies of 45 sugar maple and 45 American beech trees and associated understorey saplings in mature protected forests near Montréal. Samples were obtained by beating the crown foliage at various heights and by beating saplings around each tree.
3 Eighty-two species were identified from 13 669 individuals. Forty-eight species and 3860 individuals and 72 species and 9809 individuals were collected from the canopy and the understorey, respectively.
4 Multivariate analyses (NMDS ordination and NPMANOVA) showed the composition of canopy and understorey assemblages differed significantly, and canopy assemblages differed between tree species. Rank-abundance distribution models fitted to the canopy and understorey data indicated that different mechanisms structure the assemblages in both habitats. Three abundant spider species were significantly more common in the canopy; ten species were collected significantly more often in the understorey.
5 The forest canopy was shown to be an important reservoir for spider diversity in north-temperate forests.     

Environmental Correlates of Tree and Seedling–Sapling Distributions in a Mexican Tropical Dry Forest

Bray and Curtis ordination was used to explore which environmental variables explained importance values and the presence–absence of tropical tree seedlings, saplings and adults in La Escondida-La Cabaña, Sierra de Manantlán, Jalisco, Mexico. The diameters of trees ≥2.5 cm DBH and the presence and height of seedlings and saplings were measured in nine 0.1 ha sites. Four matrices including presence–absence data and importance value indices for trees and seedlings and saplings were analyzed through Bray and Curtis ordination. The matrices were based on density, frequency, and dominance of adult trees as well as seedlings and saplings. The environmental matrix consisted of 18 variables, including elevation, slope, canopy gaps, disturbance, and soil variables. We recorded 63 tree species and 38 seedling and sapling species in the nine sites. The ordination explained 70.9% of the variation in importance value data for trees and 62.6% for seedlings and saplings. The variation explained in presence–absence data for trees was 67.1 and 77.4% for seedlings and saplings. The variance in the ordination axes of seedlings and sapling presence–absence data was poorly explained by the number of gaps in the tree, shrub, or herb layer, suggesting little light specialization by seedlings and saplings. Habitat specialization for soil nutrients appears to be important in explaining the presence–absence of seedlings and saplings. Seedling and sapling specialization along different soil microsites could promote species coexistence in this forest, while heterogeneity in light conditions may instead determine differences in growth and, thus, importance value of trees. We hypothesize that in tropical dry forest in Jalisco, Mexico, a habitat specialization for soil resources is likely more importance at early stages in tree life histories than in later life history.     

14C transfer between the spring ephemeral Erythronium americanum and sugar maple saplings via arbuscular mycorrhizal fungi in natural stands

We investigated in the field the carbon (C) transfer between sugar maple (Acer saccharum) saplings and the spring ephemeral Erythronium americanum via the mycelium of arbuscular mycorrhizal (AM) fungi. Sugar maple saplings and E. americanum plants were planted together in pots placed in the ground of a maple forest in 1999. Ectomycorrhizal yellow birches (Betula alleghaniensis) were added as control plants. In spring 2000, during leaf expansion of sugar maple saplings, the leaves of E. americanum were labelled with ¹⁴CO₂. Seven days after labelling, radioactivity was detected in leaves, stem and roots of sugar maples. Specific radioactivity in sugar maples was 13-fold higher than in yellow birches revealing the occurrence of a direct transfer of ¹⁴C between the AM plants. The quantity of ¹⁴C transferred to sugar maple saplings was negatively correlated with the percentage of ¹⁴C allocated to the storage organ of E. americanum. A second labelling was performed in autumn 2000 on sugar maple leaves during annual growth of E. americanum roots. Radioactivity was detected in 7 of 22 E. americanum root systems and absent in yellow birches. These results suggest that AM fungi connecting different understorey species can act as reciprocal C transfer bridges between plant species in relation with the phenology of the plants involved.     

Quantitative characterization of clumping in Scots pine crowns

Background and Aims

Proper characterization of the clumped structure of forests is needed for calculation of the absorbed radiation and photosynthetic production by a canopy. This study examined the dependency of crown-level clumping on tree size and growth conditions in Scots pine (Pinus sylvestris), and determined the ability of statistical canopy radiation models to quantify the degree of self-shading within crowns as a result of the clumping effect.

Methods

Twelve 3-D Scots pine trees were generated using an application of the LIGNUM model, and the crown-level clumping as quantified by the crown silhouette to total needle area ratio (STAR_crown) was calculated. The results were compared with those produced by the stochastic approach of modelling tree crowns as geometric shapes filled with a random medium.

Key Results

Crown clumping was independent of tree height, needle area and growth conditions. The results supported the capability of the stochastic approach in characterizing clumping in crowns given that the outer shell of the tree crown is well represented.

Conclusions

Variation in the whole-stand clumping index is induced by differences in the spatial pattern of trees as a function of, for example, stand age rather than by changes in the degree of self-shading within individual crowns as they grow bigger.     

Norway Maple (Acer platanoides) Invasion of a Natural Forest Stand: Understory Consequence and Regeneration Pattern

Norway maple (Acer platanoidesis) is invasive in a natural stand in suburban Ithaca, NY. To determine the understory pattern and consequences of a Norway maple invasion, I compared density and species richness under Norway maples and sugar maples (Acer saccharum). Mean sapling density was significantly lower (P<0.0027) under Norway maples (3.64/100 m²±1.6 SE) than under sugar maples (19.4/100 m²±4.4 SE). Mean sapling species richness was significantly lower (P<0.0018) under Norway maples (0.7/32 m²±0.18 SE) than under sugar maples (2.6/32 m²±0.48 SE). Likewise, Norway maple regeneration is more frequent under sugar maples than sugar maple regeneration: 57% of sugar maple plots had Norway maple saplings while 0% of Norway maple plots had sugar maple saplings. Two significant plot effects were found for presence–absence: Norway maple saplings grow under Norway maples with a significantly lower frequency (P<0.03) than under sugar maples; sugar maple saplings grow under Norway maples with a significantly lower frequency (P<0.000) than under sugar maples. Across the site, Norway maple saplings were the most abundant (29 saplings for 480 m²). The success of Norway maple regeneration and the reductions in total stem density beneath Norway maples is most likely the result of its strong competitive abilities, notably its high shade tolerance and abundant seed crops.     

基于GreenLab的油松结构-功能模型

 植物结构-功能模型(Functional-structural models, FSMs)将结构模型与过程模型结合起来, 用以描述环境机制驱动的植物生长, 输出植物的三维结构。GreenLab是一个近年来不断发展着的基于源-汇关系的通用植物结构-功能模型, 它多应用于农作物, 在树木方面的应用还很少。该文以幼龄油松(Pinus tabulaeformis)为研究对象, 首次将GreenLab模型应用到虚拟树木生长的研究中。采用破坏性取样, 实测了9株油松幼树的形态结构、拓扑结构和器官生物量信息, 根据拓扑编码体系组织数据。模型的直接参数是通过实测数据获得的, 隐含参数是利用非线性最小二乘法拟合反求获得的。对模型的假设进行了验证, 并对模型的模拟效果进行了评估, 结果表明: 节间总鲜质量、树木叶总鲜质量、节间鲜质量、节间长度观测值和模型模拟值建立的回归方程的决定系数在0.78~0.91之间, 因此该模型较真实地反映了油松的结构和生长过程。提出的树木结构和生物量测量及编码方法, 可作为针叶树建立结构-功能模型的参照。     

Tree demography suggests multiple directions and drivers for species range shifts in mountains of Northeastern United States

Climate change is expected to lead to upslope shifts in tree species distributions, but the evidence is mixed partly due to land‐use effects and individualistic species responses to climate. We examined how individual tree species demography varies along elevational climatic gradients across four states in the northeastern United States to determine whether species elevational distributions and their potential upslope (or downslope) shifts were controlled by climate, land‐use legacies (past logging), or soils. We characterized tree demography, microclimate, land‐use legacies, and soils at 83 sites stratified by elevation (~500 to ~1200 m above sea level) across 12 mountains containing the transition from northern hardwood to spruce‐fir forests. We modeled elevational distributions of tree species saplings and adults using logistic regression to test whether sapling distributions suggest ongoing species range expansion upslope (or contraction downslope) relative to adults, and we used linear mixed models to determine the extent to which climate, land use, and soil variables explain these distributions. Tree demography varied with elevation by species, suggesting a potential upslope shift only for American beech, downslope shifts for red spruce (more so in cool regions) and sugar maple, and no change with elevation for balsam fir. While soils had relatively minor effects, climate was the dominant predictor for most species and more so for saplings than adults of red spruce, sugar maple, yellow birch, cordate birch, and striped maple. On the other hand, logging legacies were positively associated with American beech, sugar maple, and yellow birch, and negatively with red spruce and balsam fir – generally more so for adults than saplings. All species exhibited individualistic rather than synchronous demographic responses to climate and land use, and the return of red spruce to lower elevations where past logging originally benefited northern hardwood species indicates that land use may mask species range shifts caused by changing climate.     

Phylogenetic Structure of Tree Species across Different Life Stages from Seedlings to Canopy Trees in a Subtropical Evergreen Broad-Leaved Forest

Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from seedlings to canopy trees, as well as forest gap influence on the phylogenetic structure of forest regeneration in a forest of the subtropical region in China. We investigate changes in phylogenetic relatedness (measured as NRI) of tree species from seedlings, saplings, treelets to canopy trees; we compare the phylogenetic turnover (measured as β_NRI) between canopy trees and seedlings in forest understory with that between canopy trees and seedlings in forest gaps. We found that phylogenetic relatedness generally increases from seedlings through saplings and treelets up to canopy trees, and that phylogenetic relatedness does not differ between seedlings in forest understory and those in forest gaps, but phylogenetic turnover between canopy trees and seedlings in forest understory is lower than that between canopy trees and seedlings in forest gaps. We conclude that tree species tend to be more closely related from seedling to canopy layers, and that forest gaps alter the seedling phylogenetic turnover of the studied forest. It is likely that the increasing trend of phylogenetic clustering as tree stem size increases observed in this subtropical forest is primarily driven by abiotic filtering processes, which select a set of closely related evergreen broad-leaved tree species whose regeneration has adapted to the closed canopy environments of the subtropical forest developed under the regional monsoon climate.     

基于GreenLab原理构建油松成年树的结构-功能模型

 林木的结构-功能模型(functional-structural tree modeling, FSTMs)是基于器官级组件构建的将植物结构和功能结合起来的一类模型, 在应用于成年树时需要解决拓扑结构复杂性和年轮分配模式普适性的问题。该文以18年生和41年生的油松 (Pinus tabulaeformis)成年树为研究对象, 将GreenLab模型应用到成年树的模拟中。采用破坏性取样, 实测了2株油松成年树的形态结构, 利用子结构模型解决成年树拓扑结构复杂性的问题, 引入年轮影响系数λ, 将全局分配模式和Pressler模式结合起 来, 解决年轮分配模式在不同年龄和环境条件下不同的问题。模型的直接参数通过实测数据获得, 隐含参数利用非线性最小二乘法拟合反求获得。通过实测数据与模拟数据的对比、模拟数据与经验模型模拟数据的对比, 对模型的模拟效果进行了评估, 发现节间总重、针叶总重、树高、树干节间重观测值和模型模拟值建立的回归方程的决定系数为0.84–0.98, 结构-功能模型与经验模型对总生物量模拟的决定系数为0.95, 表明该模型能较真实地反映油松的结构和生长过程。