Wood Specific Gravity Variations and Biomass of Central African Tree Species: The Simple Choice of the Outer Wood

Context

Wood specific gravity is a key element in tropical forest ecology. It integrates many aspects of tree mechanical properties and functioning and is an important predictor of tree biomass. Wood specific gravity varies widely among and within species and also within individual trees. Notably, contrasted patterns of radial variation of wood specific gravity have been demonstrated and related to regeneration guilds (light demanding vs. shade-bearing). However, although being repeatedly invoked as a potential source of error when estimating the biomass of trees, both intraspecific and radial variations remain little studied. In this study we characterized detailed pith-to-bark wood specific gravity profiles among contrasted species prominently contributing to the biomass of the forest, i.e., the dominant species, and we quantified the consequences of such variations on the biomass.

Methods

Radial profiles of wood density at 8% moisture content were compiled for 14 dominant species in the Democratic Republic of Congo, adapting a unique 3D X-ray scanning technique at very high spatial resolution on core samples. Mean wood density estimates were validated by water displacement measurements. Wood density profiles were converted to wood specific gravity and linear mixed models were used to decompose the radial variance. Potential errors in biomass estimation were assessed by comparing the biomass estimated from the wood specific gravity measured from pith-to-bark profiles, from global repositories, and from partial information (outer wood or inner wood).

Results

Wood specific gravity profiles from pith-to-bark presented positive, neutral and negative trends. Positive trends mainly characterized light-demanding species, increasing up to 1.8 g.cm^-3 per meter for Piptadeniastrum africanum, and negative trends characterized shade-bearing species, decreasing up to 1 g.cm^-3 per meter for Strombosia pustulata. The linear mixed model showed the greater part of wood specific gravity variance was explained by species only (45%) followed by a redundant part between species and regeneration guilds (36%). Despite substantial variation in wood specific gravity profiles among species and regeneration guilds, we found that values from the outer wood were strongly correlated to values from the whole profile, without any significant bias. In addition, we found that wood specific gravity from the DRYAD global repository may strongly differ depending on the species (up to 40% for Dialium pachyphyllum).

Main Conclusion

Therefore, when estimating forest biomass in specific sites, we recommend the systematic collection of outer wood samples on dominant species. This should prevent the main errors in biomass estimations resulting from wood specific gravity and allow for the collection of new information to explore the intraspecific variation of mechanical properties of trees.     

Radial wood allocation in Schizolobium parahyba

? Premise of the study: Pioneer species of tropical trees allocate wood specific gravity (SG) differently across the radius. Some species exhibit relatively uniform, low SG wood, whereas many others exhibit linear increases in SG across the radius. Here, we measured changes in SG across the radius of Schizolobium parahyba (Fabaceae-Caesalpinioideae), a wide-ranging, neotropical pioneer, used extensively in land reclamation and forest restoration in Brazil. ? Methods: Pith-to-bark radial wood cores were extracted with increment borers from 42 trees at five sites, in Central and South America. Cores were cut into 1-cm segments whose specific gravities were determined and analyzed via linear and nonlinear regression. Wood specific gravity, very low initially at 0.15-0.20, doubled or tripled across the tree radius to 0.45-0.65 for large adults. ? Key results: Unlike linear increases in other tropical pioneers, the increases in Schizolobium were nonlinear (convex up). At one site with even-aged trees, the magnitude of the radial increase was similar in all trees, despite a 4-fold difference in diameter among trees, implying that the radial increases in Schizolobium were regulated by tree age, not by tree size. ? Conclusions: This unique pattern of development should provide an extended period of growth when SG is low, facilitating hyper-extension of the bole, at some risk of structural failure. Later in growth, the SG rate of increase accelerates, reinforcing what was a precarious bole. Overall, these results suggest a third model for xylem allocation in tropical trees, a model that may be associated with monopodial stem development and limited life span.     

Mechanical Properties of Black Locust (Robinia pseudoacacia) Wood: Correlations among Elastic and Rupture Moduli,Proportional Limit,and Tissue Density and Specific Gravity

The purpose of this paper is to determine the extent to which the physical and mechanical properties of dry and green wood samples are correlated. Samples of green (fresh) sap- and heartwood differing in density (ρ) were removed from the trunk of a black locust (Robinia pseudoacaciaL.) tree 30 years old and measuring 15 m in height. These samples were mechanically tested to determine their Young's elastic modulus (E), proportional (elastic) limit (σ_p), and modulus of rupture (σ_R). The Young's elastic modulus of green wood samples increased in magnitude to a limit with increasing cross-sectional area of the sample tested. The values of all three mechanical parameters measured for sapwood samples were consistently lower than those measured for heartwood samples with equivalent cross-sectional areas.Ewas linearly and positively correlated with the σ_pand σ_Rof heartwood tissue samples. All mechanical properties were highly correlated with the density of green heartwood. Likewise, these properties were highly correlated with the specific gravity of wood samples. Based on these results, it is concluded that either the density of fresh wood or the specific gravity of air-dried wood can be used to estimate the mechanical properties of black locust wood based on simple regression curves in the absence of extensive mechanical tests.     

Age versus size determination of radial variation in wood specific gravity: lessons from eccentrics

Radial increases in wood specific gravity have been shown to characterize early successional trees from tropical forests. Here, we develop and apply a novel method to test whether radial increases are determined by tree age or tree size. The method compares the slopes of specific gravity changes across a short radius and a long radius of trees with eccentric trunks. If radial changes are determined by size, then the slope of the change should be the same on both radii. If radial changes are determined by age, then the slope should be greater on the short radius. For 30 trees from 12 species with eccentricity of at least 4%, the ratio of the slopes of the linear regressions of specific gravity on radial distance (short radius slope/long radius slope) was regressed on the ratio of radii lengths (long radius/short radius). The regression was highly significant, and the faster increase in specific gravity on the short radius was sufficient to compensate for the difference in radius lengths, so the specific gravity of wood along the short radius was equal to the specific gravity on the long radius at any given proportional distance on the radius. Therefore, trees that are producing xylem faster on one radius than another produce wood of comparable specific gravity on both radii at the same time, so radial increases in specific gravity are dependent on tree age, not tree size.     

The relationship between stem and branch wood specific gravity and the ability of each measure to predict leaf area

A few trait axes that represent differential biomass allocation may summarize plant life-history strategies. Here we examine one of these axes described by wood specific gravity. Wood specific gravity represents the location of a species on a continuum of the rate of growth vs. the likelihood of mechanical failure, ranging from rapid volumetric growth/increased probability of mechanical failure to slow volumetric growth/decreased probability of mechanical failure. Wood specific gravity has been quantified primarily using three separate methods: a section from terminal branch, a section from the main stem or from a trunk wood core. What is unclear is how comparable these methods are and whether one or the other is a better predictor of other important plant traits such as leaf area. Here we measured stem and branch wood specific gravities from individual trees and shrubs in a tropical rain forest, quantified their relationship and determined their ability to predict leaf area. Stem and branch measures were highly correlated with each measure having a weak correlation with leaf area in trees and strong correlation with leaf area in shrubs. These results indicate that various methodologies for measuring wood specific gravity are comparable, and thus less destructive methods than are currently used are available to determine values for this important trait.     

Diversity in specific gravity and water content of wood among Bornean tropical rainforest trees

Wood properties were measured for trees in lowland dipterocarp forests in West Kalimantan. In 1993 and 1994, 353 samples of 286 species were collected from trunk base of trees of approximately 5 cm in diameter, and the specific gravities (SG: oven dry weight/fresh volume) and water contents of wood including bark were measured. The SG of each species ranged from 0.21 to 0.84, and the mean ± SD was 0.53 ± 0.13. The wide range of SG suggests that the forest had a high diversity in wood properties. The most dominant and diversified genus in this area was Shorea, and the SG of 15 species varied from 0.21 to 0.71. The range covered SG of pioneer (six Macaranga, 0.29–0.43) and small trees in primary forests (nine Eugenia and 10 Xanthophyllum, 0.55–0.77). The SG average for tree species of secondary forests of 2–6 years old was 0.31. It was significantly smaller than that of primary forests (0.58). In a primary dipterocarp forest plot, light-wood species grew faster in diameter than heavy-wood species. Water content ranged from 0.26 to 0.76. Heavy wood had low water content. Among light-wood species, some (Shorea, Artocarpus) had low water contents and others (Ficus) had high water contents. Some riverine trees also had high water contents. These wood properties appear strongly related to the life history of trees and successional stage.     

Tree Species Composition, Structure, and Aboveground Wood Biomass of a Riparian Forest of the Lower Miranda River, Southern Pantanal, Brazil

The aboveground wood biomass (AWB) of tropical forests plays an important role in the global carbon cycle, and local AWB estimates provide essential data that enable the extrapolation of biomass stocks to ecosystem or biome-wide carbon cycle modelling. Few AWB estimates exist in Neotropical freshwater floodplains, where tree species distribution and forest structure depend on the height and duration of periodic inundations. We investigated tree species composition, forest structure, wood specific gravity, and AWB of trees ≥10 cm dbh in 16 plots totalling an area of 1 ha in a seasonally inundated riparian forest of the lower Miranda River, southern Pantanal, Brazil. The 443 tree individuals belonged to 46 species. Four species (Inga vera, Ocotea suaveolens, Tabebuia heptaphylla and Cecropia pachystachya) comprised more than 50% of the Total Importance Values (TIV), and floristic similarities between the plots averaged 38%. Although we detected an overall increase in species diversity correlated with decreasing flood levels, the most important tree species had almost identical distribution patterns along the flooding gradient. The stand basal area per plot (±?s.d.) amounted to 3.0?±?1.1 m² (47.8?±?18.1 m²/ha), and the tree heights averaged 10.9?±?1.4 m. Multiplying the individual basal areas by individual tree heights and a form factor of 0.6, we estimated the aboveground wood volume (AWV) for each individual, and for each plot (24.4?±?11.7 m³, 391.1?±?188 m³/ha). Wood specific gravity (SG) varied between 0.39 g/cm³ (Cecropia pachystachya) and 0.87 g/cm³ (Tabebuia heptaphylla), with a stand level average of 0.63?±?0.12 g/cm³. Multiplying the individual AWV with species SG, we estimated the plot AWB to be 16.2?±?6.4 Mg (259.4?±?102 Mg/ha). This value is comparable to that reported for late-successional forest stands of Amazonian floodplain forests, and it is close to the worldwide tropical average AWB. Because tree heights in the present forest were comparatively low when compared to other Neotropical forests, we found that resprouting of stems accounted for comparatively high basal areas. We argue that stem resprouting is an adaptation of tree species originating in non-flooded Cerrado to the seasonal inundations of riparian forests.     

The Buttressed Blue Marble Tree: Wood and Growth Characteristics of Elaeocarpus angustifolius (Elaeocarpaceae)

Elaeocarpus angustifolius, a forest tree native to Australia,was introduced into the Hawaiian Islands and is now naturalizedlocally. The main purpose of this study was to test the hypothesisthat a radial increase in wood specific gravity was presentin trunk wood of these trees, which grow quite large (diameterat breast height=200 cm) and have massive buttress systems.Information on buttress height and number and specific gravityof the outer trunk wood (sampled at breast height), as wellas anatomical characteristics pertaining to conduction (vesseldiameter and density), was obtained from a range of different-sizedtrees. Both buttress height and number increase with increasingtree diameter. Wood specific gravity has a median value of 0.49and increases more than 50% over the range of tree diametersstudied. Vessel diameter increases over two-fold and vesselfrequency decreases with increasing tree diameter, althoughvery large trees (diameters>70 cm) exhibit more variability.Trees have buttresses spaced evenly around the circumference(maximum of 15–20) and exhibit no difference in wood specificgravity on the leeward and windward sides in spite of theirlocation in the trade wind belt. Radial increases in specificgravity of the type documented here may be important in evaluatingthe carbon present in forest stores. Copyright 2000 Annals ofBotany Company Buttresses, wood specific gravity, vessel diameter and density, Elaeocarpus angustifolius.     

Does canopy position affect wood specific gravity in temperate forest trees?

The radial increases in wood specific gravity known in many tree species have been interpreted as providing mechanical support in response to the stresses associated with wind loading. This interpretation leads to the hypothesis that individuals reaching the canopy should (1) be more likely to have radial increases in specific gravity and (2) exhibit greater increases than individuals in the subcanopy. Wood specific gravity was determined for three species of forest trees (Acer rubrum, Fagus grandifolia and Tsuga canadensis) growing in central Massachusetts, USA. Acer rubrum shows radial increases in specific gravity, but these increases are not more pronounced in canopy trees; the other two species show a pattern of radial decreases. The degree of radial increase or decrease is influenced by tree height and diameter. Of the dominant tree species for which we have data, A. rubrum, Betula papyrifera and Pinus strobus show radial increases in specific gravity, whereas F. grandifolia, T. canadensis and Quercus rubra show decreases. The occurrence of radial increases in B. papyrifera and P. strobus, which are often canopy emergents, suggests that it is overall adaptive strategy that is important rather than position (canopy vs. subcanopy) of any individual tree. It is suggested that radial increases in specific gravity are associated with early-successional status or characteristics and decreases with late-successional status or persistence in mature forest.     

Radial Gradients in Wood Specific Gravity,Water and Gas Content in Trees of a Mexican Tropical Rain Forest

Cell walls, water, and gas that have mechanical and physiological functions in wood, and wood specific gravity (WSG) is related to demographic traits. To understand variation in wood structure and function, we analyzed radial changes in WSG, in the gas and the water fractions from trees growing in four different habitats in a southern Mexican rain forest. Mean WSG was 0.55 ± 0.16, slightly lower than reported for other tropical forests. In 27 species, WSG decreased and in two species, it increased from pith to bark with a strong (r² = 0.65) negative correlation between WSG in the center of the tree and the radial WSG gradient. Habitat had some effect on mean WSG and trees growing on karst had significantly higher WSG than the same species growing on alluvial soil. The cell wall, water, and gas fractions accounted for 35 percent (range: 16–50), 42 percent (28–65), and 23 percent (2–56), respectively, of wood volume, with a negative correlation between the gas and the cell wall and between the gas and the water fractions, but not between the cell wall and water fractions. Radially increasing WSG is advantageous for pioneer trees with fast initial growth. We found that the water displacement method may result in biased WSG estimates. To increase the accuracy of WSG data, we suggest to measure sample volume geometrically using a constant diameter (that of the borer tip), to include radial variation in WSG, and to consider for possible site effects on species‐specific WSG.     

A conceptual guide to measuring species diversity

Three metrics of species diversity – species richness, the Shannon index and the Simpson index – are still widely used in ecology, despite decades of valid critiques leveled against them. Developing a robust diversity metric has been challenging because, unlike many variables ecologists measure, the diversity of a community often cannot be estimated in an unbiased way based on a random sample from that community. Over the past decade, ecologists have begun to incorporate two important tools for estimating diversity: coverage and Hill diversity. Coverage is a method for equalizing samples that is, on theoretical grounds, preferable to other commonly used methods such as equal-effort sampling, or rarefying datasets to equal sample size. Hill diversity comprises a spectrum of diversity metrics and is based on three key insights. First, species richness and variants of the Shannon and Simpson indices are all special cases of one general equation. Second, richness, Shannon and Simpson can be expressed on the same scale and in units of species. Third, there is no way to eliminate the effect of relative abundance from estimates of any of these diversity metrics, including species richness. Rather, a researcher must choose the relative sensitivity of the metric towards rare and common species, a concept which we describe as ‘leverage.' In this paper we explain coverage and Hill diversity, provide guidelines for how to use them together to measure species diversity, and demonstrate their use with examples from our own data. We show why researchers will obtain more robust results when they estimate the Hill diversity of equal-coverage samples, rather than using other methods such as equal-effort sampling or traditional sample rarefaction.     

Stem growth rhythms in trees of a tropical rainforest in Southern Brazil

Key message

We demonstrate that tropical trees growing in wet climates can have a marked seasonality in cambium activity and stem growth associated with high temperature and day length of summer.

Abstract

Monitoring the rhythm of tree growth associated with the growth rings can contribute substantially to understanding forest dynamics and the management of tropical forests. In this study, we monitored the girth increment rhythm and described the wood characteristics (anatomy of growth rings, wood specific gravity) in 10 tropical tree species (103 individuals) naturally occurring in a wet and weakly seasonal region of Atlantic Forest in southern Brazil. We aimed to verify whether tree growth dynamics are associated with climate and woody anatomy in tropical trees with contrasting ecological characteristics. We installed permanent dendrometer bands and monthly assessed the girth increment for 22 months. We collected wood samples (non-destructive method), measured wood specific gravity and prepared permanent slides to characterize the growth ring markers. We found growth rings in all species (distinct in six species); deciduous species produced more distinguishable tree rings compared with semi-deciduous and evergreen tree species. Species varied in their accumulated girth growth (in average, from 1.83 to 62.64 mm), growth rates (1–15 %), and annual radial increment (0.16–5.44 mm). Girth increment was positively related to temperature and day length in five out of ten tree species, indicating the possible effects of these climatic variables in triggering cambial activity in these species. The growth pattern varied among species and was marginally associated to the tree deciduousness. We concluded that even in wet and less seasonal climates, there can be an association in the cambium activity and stem growth with the hotter and longer days of summer months.

     

On estimating the precision of stable isotope ratios in processed tree-rings

Stable isotope dendrochronology is a well-developed field of research, but improvements to methodologies are on-going. We propose an improved method for estimating the precision of stable isotope ratios (δ) of tree-ring samples that are processed from whole wood to various end products such as cellulose-nitrate, α-cellulose, or cellulose intermediates. The status quo method for estimating the δ precision of organic solids is to characterise the long-term 2-sigma range of δ values for a ready-made Quality Assurance (QA) standard that is included in each analysis run of samples. While the status quo method is appropriate for characterising analytical uncertainties associated with the mass spectrometer, combustion or pyrolysis system, and analyte specifics, it does not reflect uncertainties associated with sample processing from inadvertent and unrealised operator error (e.g., contamination by airborne particles, incomplete chemical processing, sample storage issues, and other unforeseen errors), although such errors would probably be rare with an experienced operator. The proposed method improves upon the status quo method as it respects the Identical Treatment principle by subjecting QA standards to the same processing steps that samples undergo. As such, analytical uncertainties associated with sample processing would be integrated into the QA standard's δ value and precision estimate. In effect, the proposed method is a system to monitor inter-batch reproducibility and, by the same token, can be used to identify batches that were potentially compromised during processing. A pilot study example is used to demonstrate the proposed method for δ¹⁸O analysis of α-cellulose samples.     

Urinary and hematologic indexes of hypohydration

As part of a large-scale field feeding system test we were able to collect and study hundreds of aliquots of overnight urine samples obtained immediately prior to a fasting blood sample on days 1, 20, and 44 of the field test. The large number of experimental samples (greater than 650) and concomitant collection of blood and urine aliquots along with data on body weights gave us the opportunity to assess and quantitate the sensitivity of commonly used criteria of hypohydration. Urine aliquots for all test days were initially categorized by specific gravity (SG) greater than or equal to 1.03 (n = 124) or less than 1.03 (n = 540). Creatinine levels were elevated (P less than 0.001) in the concentrated urine samples, but a decreased trend in sodium-to-potassium ratios in these samples failed to achieve statistical significance (P greater than 0.05). However, when individuals with high SG urine were subclassified by a criterion of weight loss greater than 3% from original body weight, then creatinine concentrations were elevated (P = 0.05), whereas sodium-to-potassium ratios were decreased (P = 0.05) when subjects also with high SG but weight loss less than 3% were compared. Because of the moderate altitude (2,000 m) of the field site and the time of sojourn (44 days), there occurred a slight, but significant (P less than 0.001), erythropoietic response. Hematocrit and serum osmolality were not significantly different when examined by the criteria of high or low SG urine and weight loss greater than or less than 3% original body weight.(ABSTRACT TRUNCATED AT 250 WORDS)     

Genetic Mapping of Quantitative Trait Loci Controlling Growth and Wood Quality Traits in Eucalyptus Grandis Using a Maternal Half-Sib Family and Rapd Markers

Quantitative trait loci (QTL) mapping of forest productivity traits was performed using an open pollinated half-sib family of Eucalyptus grandis. For volume growth, a sequential QTL mapping approach was applied using bulk segregant analysis (BSA), selective genotyping (SG) and cosegregation analysis (CSA). Despite the low heritability of this trait and the heterogeneous genetic background employed for mapping. BSA detected one putative QTL and SG two out of the three later found by CSA. The three putative QTL for volume growth were found to control 13.7% of the phenotypic variation, corresponding to an estimated 43.7% of the genetic variation. For wood specific gravity five QTL were identified controlling 24.7% of the phenotypic variation corresponding to 49% of the genetic variation. Overlapping QTL for CBH, WSG and percentage dry weight of bark were observed. A significant case of digenic epistasis was found, involving unlinked QTL for volume. Our results demonstrate the applicability of the within half-sib design for QTL mapping in forest trees and indicate the existence of major genes involved in the expression of economically important traits related to forest productivity in Eucalyptus grandis. These findings have important implications for marker-assisted tree breeding.     

Wood remains from Tel Nami,a middle bronze IIa and late bronze IIb port,local exploitation of trees and levantine cedar trade

Thirteen Middle Bronze Age IIa and four Late Bronze Age IIb (ca. 1950-1750 B.C. and thirteenth century, B.C., respectively)pieces of charcoal or water logged wood were found in the recent excavations of Tel Nami, a small port on the coast near Mount Carmel, Israel. These includedCedrus libani (cedar of Lebanon) (three samples), and local tree species that still grow today in the vicinity of the site—Pinus halepensis (Aleppo pine) (one sample),Olea europaea (olive tree) (five samples),Quercus calliprinos (kermes oak) (three samples),Quercus ithaburensis (Mt. Tabor oak) (four samples), andQuercus sp. (one sample). The discovery of Cedrus libani in a Middle Bronze Age IIa port is one of the earliest published examples of cedar wood from Israel. Together with other artifactual evidence for maritime trade from Tel Nami, this find suggests that a maritime trade in cedar wood existed along the Levantine coast.     

Significant deviations from Hardy-Weinberg equilibrium caused by low levels of microsatellite genotyping errors

Microsatellite genotyping from samples with varying quality can result in an uneven distribution of errors. Previous studies reporting error rates have focused on estimating the effects of both randomly distributed and locus‐specific errors. Sample‐specific errors, however, can also significantly affect results in population studies despite a large sample size. From two studies including six microsatellite markers genotyped from 272 sperm whale DNA samples, and 33 microsatellites genotyped from 213 bowhead whales, we investigated the effects of sample‐ and locus‐specific errors on calculations of Hardy–Weinberg equilibrium. The results of a jackknife analysis in these two studies identified seven individuals that were highly influential on estimates of Hardy–Weinberg equilibrium for six different markers. In each case, the influential individual was homozygous for a rare allele. Our results demonstrate that Hardy–Weinberg P values are very sensitive to homozygosity in rare alleles for single individuals, and that > 50% of these cases involved genotype errors likely due to low sample quality. This raises the possibility that even small, normal levels of laboratory errors can result in an overestimate of the degree to which markers are out of Hardy–Weinberg equilibrium and hence overestimate population structure. To avoid such bias, we recommend routine identification of influential individuals and multiple replications of those samples.     

Mapping Tropical Forest Trees Using High‐Resolution Aerial Digital Photographs

The spatial arrangement of tree species is a key aspect of community ecology. Because tree species in tropical forests occur at low densities, it is logistically challenging to measure distributions across large areas. In this study, we evaluated the potential use of canopy tree crown maps, derived from high‐resolution aerial digital photographs, as a relatively simple method for measuring large‐scale tree distributions. At Barro Colorado Island, Panama, we used high‐resolution aerial digital photographs (~0.129 m/pixel) to identify tree species and map crown distributions of four target tree species. We determined crown mapping accuracy by comparing aerial and ground‐mapped distributions and tested whether the spatial characteristics of the crown maps reflect those of the ground‐mapped trees. Nearly a quarter (22%) of the common canopy species had sufficiently distinctive crowns to be good candidates for reliable mapping. The errors of commission (crowns misidentified as a target species) were relatively low, but the errors of omission (missed canopy trees of the target species) were high. Only 40 percent of canopy individuals were mapped on the air photographs. Despite failing to accurately predict exact abundances of canopy trees, crown distributions accurately reproduced the clumping patterns and spatial autocorrelation features of three of four tree species and predicted areas of high and low abundance. We discuss a range of ecological and forest management applications for which this method can be useful.     

The effect of individual genetic heterozygosity on general homeostasis,heterosis and resilience in Siberian larch (Larix sibirica Ledeb.) using dendrochronology and microsatellite loci genotyping

The genetic mechanisms underlying the relationship of individual heterozygosity (IndHet) with heterosis and homeostasis are not fully understood. Such an understanding, however, would have enormous value as it could be used to identify trees better adapted to environmental stress. Dendrochronology data, in particular the individual average radial increment growth of wood measured as the average tree ring width (AvTRW) and the variance of tree ring width (VarTRW) were used as proxies for heterosis (growth rate measured as AvTRW) and homeostasis (stability of the radial growth of individual trees measured as VarTRW), respectively. These traits were then used to test the hypothesis that IndHet can be used to predict heterosis and homeostasis of individual trees. Wood core and needle samples were collected from 100 trees of Siberian larch (Larix sibirica Ledeb.) across two populations located in Eastern Siberia. DNA samples were obtained from the needles of each individual tree and genotyped for eight highly polymorphic microsatellite loci. Then mean IndHet calculated based on the genotypes of eight loci for each tree was correlated with the statistical characteristics of the measured radial growth (AvTRW and VarTRW) and the individual standardized chronologies. The analysis did not reveal significant relationships between the studied parameters. In order to account for the strong dependence of the radial growth on tree age the age curves were examined. An original approach was employed to sort trees into groups based on the distance between these age curves. No relationship was found between these groups and the groups formed based on heterozygosity. However, further work with more genetic markers and increased sample sizes is needed to test this novel approach for estimating heterosis and homeostasis.