Eucalyptus Plantations In Brazil Research Articles

Lessons from the Incursion of Myrtle Rust in Australia.

Austropuccinia psidii (myrtle rust) is a globally invasive neotropical rust of the Myrtaceae that came into international prominence following extensive damage to exotic Eucalyptus plantations in Brazil in the 1970s and 1980s. In 2005, myrtle rust established in Hawaii (USA), and over the past 12 years has spread from the Americas into Asia, the Pacific, and South Africa. Myrtle rust was detected in Australia in 2010, and the response and ultimately unsuccessful eradication attempt was a lesson to those concerned about the threat of exotic pests and diseases to Australia's environment. Seven years following establishment, we are already observing the decline of many myrtaceous species and severe impacts to native plant communities. However, the recently developed Myrtle rust in Australia draft action plan identified that there is no nationally coordinated response strategy for the environmental dimensions of this threat. Recent reviews have identified a greater need for involvement from environmental agencies in biosecurity preparedness, response, and resourcing, and we believe this approach needs to extend to the management of invasive environmental pathogens once they establish.

Genomic analysis of a cypovirus isolated from the eucalyptus brown looper, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae)

The eucalyptus brown looper, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae), is the main lepidopteran defoliator of eucalyptus plantations in Brazil. Outbreaks of this insect pest are common in Brazil and can affect the productivity of planted forests severely. T. arnobia caterpillars from a laboratory colony with viral infection symptoms were analyzed by electron microscopy that revealed polyhedral occlusion bodies (OBs) with several icosahedral virus particles embedded. Analysis of its genetic material showed ten segments of dsRNA, which confirmed this virus as a possible member of the genus Cypovirus. Phylogenetic analysis of the whole genome sequence revealed its close relationship with other isolates of Cypovirus 14 species and according to these results we proposed the name Thyrinteina arnobia cypovirus 14 (TharCPV-14) for this new virus isolate. Further research will be necessary in order to analyze the potential of this virus as a biopesticide.

Thinning regimes and initial spacing for Eucalyptus plantations in Brazil.

This study focuses on the effects of different thinning regimes on clonal Eucalyptus plantations growth. Four different trials, planted in 1999 and located in Bahia and Espírito Santo States, were used. Aside from thinning, initial planting density, and post thinning fertilization application were also evaluated. Before canopy closure, and therefore before excessive competition between trees took place, it was found that stands planted under low densities (667 trees per hectare) presented a lower mortality proportion when compared to stand planted under higher densities (1111 trees per hectare). However, diameter growth prior to thinning operations was not statistically different between these two densities, presenting an overall mean of 4.9 cm/year. After canopy closure and the application of the thinning treatments, it was found that thinning regimes beginning early in the life of the stand and leaving a low number of residual trees presented the highest diameter and height growth. Unthinned treatments and thinning regimes late in the life of the stand (after 5.5 years), leaving a large number of residual trees presented the highest values of basal area production. The choice of the best thinning regime for Eucalyptus clonal material will vary according to the plantation objective.

Decomposition of eucalypt harvest residues as affected by management practices, climate and soil properties across southeastern Brazil

Across southeastern Brazil, eucalypt plantations have been established in areas with predominantly low-fertility soils, in which nutrient cycling is critical for forest sustainability. However, despite continuous research on harvest residues (HR) over the last 30years or more, the extent by which its decomposition rate is affected by management practices, climate conditions and soil properties is not well understood. We evaluated the decomposition of HR in 10 sites under eucalypt plantations within the Mata Atlântica and the Cerrado (savanna-like) biomes, which account for more than 60% of the area under eucalypt plantations in Brazil. In each site, we assessed the decomposition of HR as affected by three major management practices, namely bark removal or its maintenance, HR left on the soil surface or mixed into the topsoil, and N fertilization at 0 or 200kgha−1, in a complete factorial scheme, using 4 replicates per treatment. The remaining mass of HR was assessed at 0, 3, 6, 12 and 36months after the installation of the experiments, yielding a total of 320 samples. HR decomposed 22% faster when it was mixed into the topsoil or when the bark was included, but it was minimally affected by N fertilization. While increasing precipitation, temperature, soil pH, exchangeable Ca and Mg, and sand content led to faster decomposition rates, the opposite occurred with increasing exchangeable Al and clay content. The mean annual precipitation and soil pH combined by multiple linear regressions explained approximately 70% of the variability in the decomposition of HR across the sites. Interestingly, the decomposition rate was inversely correlated to the soil carbon content in our study. Bark maintenance in the fields under eucalypt plantations reduces off-site nutrient exportation and contributes to an increase in the decomposition rate almost by the same extent as by incorporating HR into the topsoil. Additionally, environmental conditions and soil properties also exert strong influence over the decomposition of HR and should be considered for managing nutrient cycling and fertilization programs. This is particularly important for the sustainability of eucalypt plantations established in low-fertility soils across tropical regions.

A principal component approach for predicting the stem volume in Eucalyptus plantations in Brazil using airborne LiDAR data

Improving management practices in industrial forest plantations may increase production efficiencies, thereby reducing pressures on native tropical forests for meeting global pulp needs. This study aims to predict stem volume (V) in plantations of fast-growing Eucalyptus hybrid clones located in southeast Brazil using field plot and airborne Light Detection andRanging (LiDAR) data. Forest inventory attributes and LiDAR-derived metrics were calculated at 108 sample plots. The best LiDAR-based predictors of V were identified based on loadings calculated from a principal component analysis (PCA). After selecting these best predictors using PCA,we developed multiple regression models predicting V from selected LiDAR metrics. Metrics related to tree height and canopy depth were most effective for V prediction, with an overall model coefficient of determination (adj. R2) of 0.87, and a root mean squared error (RMSE) of 27.60 m3 ha-1 (i.e. relative RMSE = 9.99 per cent).We used this model to map stem V of Eucalyptus hybrid clones across the full LiDAR data extent. The accuracy and precision of our results show that LiDAR-derived V is appropriate for updating Eucalyptus forest base maps and registries in the paper and pulp supply chain. However, further studies are necessary to evaluate and compare the cost of acquisition and processing of LiDAR data against conventional V inventory in this system.

Expression of thenifHgene in diazotrophic bacteria inEucalyptus urograndisplantations

A large proportion of eucalypt plantations in Brazil are located in areas with low soil fertility. The actions of microorganisms are of great importance for the cycling of nutrients, including nitrogen (N), that are essential for plant metabolism. Denaturing gradient gel electrophoresis (DGGE) was used to monitor and identify the total and active microorganisms involved in the N cycle in both the soil and root systems of a forest of Eucalyptus urograndis with sections that were fertilized with N or unfertilized. Quantitative real-time PCR was used to examine the expression of the nifH gene in N-fixing bacteria present in both the soil and root systems. According to the DGGE analysis, in the total and active populations of N-fixing bacteria, the presence and expression of the nifH gene were influenced by the winter and summer seasons and (or) N fertilization, respectively. DGGE band sequencing from total DNA samples showed that the most abundant group of diazotrophic bacteria belonged to Alphaproteobacteria in both the soil and root systems. Quantitative real-time PCR revealed that nifH expression was higher in the soil samples, especially in those that did not receive N fertilization. The differences in the composition of the total and active diazotrophic populations highlight the importance of evaluating the active populations, because they are effectively responsible for the biogeochemical transformation of N and also control its’ availability to plants.

Responses of Clonal Eucalypt Plantations to N, P and K Fertilizer Application in Different Edaphoclimatic Conditions

Eucalypt plantations in Brazil have the highest mean productivity when compared to other producing countries, and fertilizer application is one of the main factors responsible for these productivities. Our aim was to identify appropriate rates of N, P and K in eucalypt plantations and their interactions with edaphoclimatic factors. Four trials with four rates and three nutrients (N, P and K) were set up. Each nutrient was studied separately, and the trees received sufficient rates of all of the other nutrients through fertilization, to avoid limitations not related to the desired nutrient. We assessed solid wood volume (SV), productivity gains (PG), leaf nutrient content and leaf area index (LAI) to determine the responses to fertilization. PG, regarding N, rates ranged from 104% to 127% at 60 months after planting. P fertilizer application led to gains in productivity in soils with levels of P-resin up to 5 mg·kg−1, but decreased with stand age. K fertilizer application responses increased within age in three sites. In Paulistania, responses to K application were close to zero. N and K responses were climate related. Leaf nutrient content and LAI were not able to predict the highest yields obtained.

HALOXIFOPE-P-METÍLICO PARA CONTROLE DE BRACHIARIA DECUMBENS NA CULTURA DO EUCALIPTO

RESUMO A cultura do eucalipto expandiu-se para a região Centro-Oeste do País, áreas onde antes havia pastagens, sobretudo de Brachiaria decumbens(capim-braquiária), passando essa a se constituir a principal planta daninha. O presente trabalho objetivou avaliar a eficácia haloxifope-p-metílico no controle de B. decumbens infestando mudas de eucalipto (Eucalyptus urograndis) e sua seletividade para a cultura. Para tanto, montou-se um experimento com três situações: eucalipto plantado isoladamente, eucalipto em convivência com a espécie B. decumbens e B. decumbens plantada isoladamente. Aos 67 dias após o plantio das mudas foi feita a aplicação do haloxifope-p-metílico nas doses de 0; 48 e 96 g.i.a.ha-1. A aplicação de haloxifope-p-metílico, na maior dose (96 g.i.a.ha-1), proporcionou um bom controle da planta daninha. O herbicida, nas doses testadas, foi seletivo à cultura do eucalipto e a convivência entre eucalipto e B. decumbens resultou em interferência negativa para ambas as espécies.

Effects of silvicultural treatments on temporal variations of spatial autocorrelation in Eucalyptus plantations in Brazil

We examined the change in spatial structures of Eucalyptus plantations across different types of silvicultural treatments over a full rotation. Clonal and seed-origin Eucalyptus plots applied with differing levels of fertilization (high vs. traditional) and irrigation (irrigated vs. non-irrigated) treatments were investigated. Additionally, for the clonal plots, uniform vs. heterogeneous stand structure treatments were created using staggered planting dates. The heterogeneous structure of the clonal plots aimed to mimic the seed-origin plots. Spatial structures were characterized by assessing the spatial autocorrelations of diameters, heights, and biomass. We also applied two distance-based neighborhood structures to look at the degree of change in spatial autocorrelations with different numbers of neighboring trees being defined as neighbors. The results suggest that spatial autocorrelations of diameters, heights, and biomass of Eucalyptus plantations were mostly insignificant at an alpha level of 0.05 over the rotation. However, spatial autocorrelations in most plots after the middle of the rotation were predominantly negative, indicating the occurrence of size differences among neighboring trees. In particular, general declining patterns from positive to negative spatial autocorrelations in diameters and biomass, except for plots with the heterogeneous stand structures, were noted at plots treated with high levels of fertilizer. This suggests that high fertilization may have influenced the realizations of microsite effects in the early stage of stand development. General trends in spatial autocorrelations between the two neighborhood structures considered were mostly similar except for several plots differing in intensities of spatial autocorrelations over the rotation.

Environmental analysis of Eucalyptus timber production from short rotation forestry in Brazil

There was a fast increase in the planted area of forest plantations in Brazil in the period from 1966 until the beginning of the 1980s due to governmental fiscal incentives, when management practices were adopted from agriculture, which raised environmental concerns. Research investigation has been conducted in order to better adapt the management of these plantations. However, in the last decade, new societal demands towards the sustainability of short rotation Eucalyptus plantations have arisen. Therefore, the goal of the study was to assess the carbon and energy balance and the release of nutrifying agents to the environment of timber production from a short rotation Eucalyptus plantation in Brazil. The Life Cycle Assessment methodology was applied and the impact categories global warming potential, eutrophication potential and cumulative energy demand were used. The results showed that for each ton of timber delivered at the mill gate, 42.49 kg CO2-eq. was released to the air, 0.240 kg PO43- eq. was released to water and air and 830 MJ-eq. of fossil energy was consumed. The forest process was responsible for 86.2% and 97.5% of global warming potential and eutrophication potential, respectively, whereas the upstream process was responsible for 58.7% of cumulative energy demand. However, the CO2-eq and energy ratios were 43.15 and 23.13, respectively. Moreover, eutrophication seems to be overestimated when compared to studies that measured nutrient leaching in conditions similar to this study. Therefore, short rotation Eucalyptus plantations proved to be sustainable systems to produce timber for several uses in Brazil.

Doses of N, P and K in the cultivation of eucalyptus in soil originally under Cerrado vegetation

Many eucalyptus plantations in Brazil are in areas of soil with low fertility, with little phosphorous (P) and potassium (K) availability and with low organic matter (OM) content, resulting in a low supply of nutrients to plants, directly reflected in reduced yield. Thus, our objective was to evaluate the effects of nitrogen (N), P and K fertilization on the growth of eucalyptus plants, with the aim of achieving nutritional balance and high yield. The experiment was conducted on Renascenca Farm, an agricultural property administered by Cargill Agricola S.A., located in the city of Tres Lagoas, Mato Grosso do Sul state, Brazil. The experimental design consisted of randomized blocks with ten treatments and five replicates. The treatments were composed of doses of N (0, 70, 105 and 140 kg ha-1), doses of P (0,40, 70 and 100 kg ha-1 of P2O5) and doses of K (0, 90, 135 and 180 kg ha-1 of K2O). The doses of N and K were applied at planting and as top dressing, and the doses of P were applied only at planting. The diameter at breast height (DBH), plant height and timber volume with bark were assessed, and the concentrations of macronutrients in the leaves were determined. DBH and volume were positively affected by N fertilization, and eucalyptus growth in DBH, height and volume increased with P and K fertilization. The maximum yield of eucalyptus at 21 months of age was obtained with the application of 71 kg ha-1 of N, 100 kg ha-1 of P2O5 and 125 kg ha-1 of K2O. The concentrations of macronutrients were adequate even in the absence of the application of N, P and K. With increasing doses of K, there was na increase in leaf concentrations of K and a decrease in those of calcium and magnesium.

PRIMEIRO REGISTRO DE DESCASCAMENTO DE <i>Eucalyptus </i>spp. POR MACACOS-PREGO (<i>Sapajus nigritus</i>, PRIMATES: CEBIDAE)

http://dx.doi.org/10.5902/1980509818469Conflitos envolvendo animais selvagens e plantios comerciais têm sido comumente registrados em todo o mundo, incluindo o descascamento de árvores nativas ou exóticas por primatas. No sul do Brasil, o macaco-prego (Sapajus nigritus) é responsável por provocar danos em plantios comerciais de Pinus spp e Araucaria angustifolia. Nesse artigo, apresentamos de forma inédita na literatura o descascamento de Eucalyptus spp. por macacos-prego. Considerando o crescimento das áreas com plantios de eucaliptos no Brasil e países vizinhos, a informação apresentada aqui é de grande importância para a economia florestal. Ele também ressalta a necessidade de estudos científicos que visem minimizar os danos causados à produção sem comprometer a conservação da vida selvagem, como aqueles que visam monitorar a disponibilidade de recursos alimentares (principalmente frutos) em fragmentos de floresta nativa e incrementá-la por meio da recuperação de áreas depauperadas ou ainda aqueles que buscam compostos naturais deterrentes.

Diversity and potential impact of Calonectria species in Eucalyptus plantations in Brazil.

Species in the genus Calonectria (Hypocreales) represent an important group of plant pathogenic fungi that cause serious losses to plant crops in tropical and subtropical climates. Calonectria leaf blight is currently one of the main impediments to Eucalyptus cultivation in Brazil, and various species of Calonectria have been associated with this disease. Since most previous identifications were solely based on morphological characters, much of the published literature needs to be re-evaluated. The aim of this study was thus to identify and determine the phylogenetic relationships among species that occur in the Eucalyptus growing regions of Brazil by using partial sequences of the β-tubulin, calmodulin, translation elongation factor 1-α and histone H3 gene regions. Based on extensive collections from soil and infected eucalypt leaf samples from plantations, phylogenetic inference revealed the Ca. pteridis complex to be the most common species complex present in Eucalyptus plantations in Brazil. By elucidating taxa in the Ca. pteridis, Ca. cylindrospora and Ca. candelabra species complexes, 20 novel Calonectria species were identified, and a new name in Calonectria provided for Cylindrocladium macrosporum as Ca. pseudopteridis.

First Report of Puccinia psidii (Myrtle Rust) in Eucalyptus Plantations in Australia.

Puccinia psidii Winter (myrtle rust, eucalyptus rust) is a significant pathogen of Eucalyptus plantations in Brazil, causing reduced growth, stem malformation, and in severe cases, tree death (3). It has a wide host range in the Myrtaceae, with over 445 species in more than 72 genera (4). As such, P. psidii has long been a threat to Australia, where many ecosystems are dominated by Myrtaceae and industries are reliant on myrtaceous hosts, including almost 1 million hectares of eucalypt plantations. In April 2010, P. psidii was detected in Australia (2) and is now established along the east coast from southern New South Wales to far north Queensland (1,5). Although known to cause severe damage to eucalypt seedlings and coppice in native forests (5), it had not been found affecting eucalypt plantations in Australia. Surveys for P. psidii were thus initiated in eucalypt plantations in NSW from the central coast (33°06'40.0″ S, 151°18'13.8″ E) to the NSW-Queensland border, encompassing 55 plantations. Two to four 100-tree transects were conducted per plantation, during spring and summer. Symptoms were first detected in December 2011 in a 6-month-old Eucalyptus agglomerata Maiden plantation on the central coast. Further surveys until summer 2014 identified P. psidii on E. pilularis Sm., E. cloeziana F. Muell., and E. grandis (Hill) Maiden in young plantations from the central coast to the north coast (30°24'20.2″ S, 152°55'57.9″ E) of NSW. Necrotic lesions and yellow pustules typical of P. psidii were present on immature leaves and shoots, often causing leaves to buckle and die. Urediniospores were globose to subglobose, yellowish brown, 15 to 20 × 18 to 23 μm, single-celled, and finely echinulate, with a prominent tonsure on the majority of spores. Teliospores were cylindrical to ellipsoidal with a rounded apex, tan brown, 25 to 45 × 15 to 25 μm, and two-celled, with remnants of a pedicel. These morphological characteristics are consistent with those of P. psidii from Australia and elsewhere (5). Simple Sequence Repeats developed from genome sequencing of an Australian isolate of P. psidii revealed no variation among 15 isolates of P. psidii from Australia and Hawaii, including an isolate from an E. pilularis plantation in NSW (K. S. Sandhu and R. F. Park, unpublished), corroborating the morphological identification. This is the first report of this significant pathogen in eucalypt plantations in Australia. P. psidii was found in only five plantations during the current surveys, in trees 6 months to 2 years old, with only a low incidence (1%) per plantation. Repeat surveys revealed no ongoing disease in the same plantations after trees were three years of age. Moreover, P. psidii was found only in plantations surrounded by native forest stands, which harbor a large reservoir of susceptible hosts, such as Rhodamnia rubescens (Benth.) Miq. The strain of P. psidii that entered Australia is currently not causing serious disease in eucalypt plantations. However, there is a need to continue quarantine restrictions to reduce the chance of another, more aggressive strain of P. psidii entering Australia.

Resistance of Eucalyptus pellita to rust (Puccinia psidii)

Eucalypts rust (Puccinia psidii) is currently one of the major diseases in commercial eucalypt plantations in Brazil. The primary method of disease control is the use of resistant genotypes, and, among the different species of Eucalyptus, E. pellita is indicated as a promising source of resistance. In this work, the genetic control of rust resistance in E. pellita through inoculations under controlled conditions of 441 plants from four full-sibling families was studied. Inoculations were performed using the monopostular isolate UFV-2, race 1. All families tested segregated for rust resistance, and the number of resistant plants was higher than susceptible in all crosses. Inheritance models based on few genes did not fully explain the observed segregation patterns, and the narrow-sense heritability of rust resistance was estimated between 32.7% and 37.3%. The results suggested that rust resistance in E. pellita is complex and is controlled by major- and minor-effect genes.

Mapping short-rotation plantations at regional scale using MODIS time series: Case of eucalypt plantations in Brazil

Short-rotation plantations are extending worldwide due to the increased demand for pulp and wood. Reliable estimations of recent expansion of short-rotation plantation areas and associated land use changes are a prerequisite to assess their environmental impact on regional carbon and water cycles, and on climate. A binary classification methodology using MODerate resolution Imaging Spectroradiometer (MODIS) 16-day 250m NDVI time series was developed and applied to classify Eucalyptus plantations across Brazil. The identification of Eucalyptus plantations specific patterns in the time series was based on the calculation of matching functions between the NDVI time series and a ~2years long reference time series. Among the seven tested matching functions, the bounding envelope was the most successful. This method was robust to residual noise on the NDVI time series, and a threshold coefficient for the binary classification was adjusted using an omission-commission criteria. With this method, it was possible to detect any presence of Eucalyptus between 2003 and 2009 at monthly time-steps, including the periods of bare soils between two rotations that are typically 6–7 years long. The dates of first afforestation, of clear-cut at the end of a rotation, and of re-planting at the beginning of a new rotation were retrieved from the NDVI time series with a precision of ~66days. The final almost continuous tri-dimensional map (space and time) was validated with three different datasets, from local to regional data. All three datasets gave similarly high global accuracy statistics, but a global underestimation of Eucalyptus areas compared to large scales census was observed. Discrepancies and way to improve the Eucalyptus area estimates were discussed in this study. The developed methodology could be applied to other short-rotation tree plantations.

Testing Different Methods of Forest Height and Aboveground Biomass Estimations From ICESat/GLAS Data in Eucalyptus Plantations in Brazil

The Geoscience Laser Altimeter System (GLAS) has provided a useful dataset for estimating forest heights in many areas of the globe. Most of the studies on GLAS waveforms have focused on natural forests and only a few were conducted over forest plantations. This work set out to estimate the stand-scale dominant height and aboveground biomass of intensively managed Eucalyptus plantations in Brazil using the most commonly used models developed for natural forests. These forest plantations are valuable case studies, with large and numerous stands that are very uniform, in which field measurements are precise compared to natural forests. The height of planted Eucalyptus forest stands estimated from waveforms acquired by GLAS were compared with in situ measurements in order to determine the model that produced the best forest height estimates. For our slightly sloping study site , the direct method defined as the difference between the signal begin and the ground peak provided forest height estimates with an accuracy of 2.2 m. The use of statistical models based on waveform metrics and digital elevation models provided slightly better results (1.89 m accuracy) in comparison with the direct method and the most relevant metrics proved to be the trailing edge extent and the waveform extent. Moreover, a power law model was used to fit in situ aboveground biomass to in situ forest height. The results using this model with GLAS-derived heights showed an accuracy for biomass of 16.1 Mg/ha.

Converging patterns of vertical variability in leaf morphology and nitrogen across seven Eucalyptus plantations in Brazil and Hawaii, USA

Key message Across sites in Brazil and Hawaii, LMA and N mass were strongly correlated with height and shade index, respectively, which may help simplify canopy function modeling of Eucalyptus plantations.

A New Species ofMegastigmus(Hymenoptera: Torymidae: Megastigminae) from Brazil

In this paper a new parasitoid Megastigmus Dalman, 1820 (Hymenoptera: Chalcidoidea: Torymidae: Megastigminae) species was described in the subgenus Torymus, associated with the gall-forming Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) in eucalypt plantations in Brazil.

Modifying the G’DAY process-based model to simulate the spatial variability of Eucalyptus plantation growth on deep tropical soils

Large differences in productivity have been observed between neighboring Eucalyptus plantations in Brazil, that cannot be explained by climate and are unlikely to be due solely to altered management practices. Current ecophysiological models used by forestry companies to simulate stand development in large plantation zones rely on empirical site fertility indices (representing water and nutrient availability) to capture this spatial variability in growth rates. We propose a model that requires no empirical assessment of site fertility to simulate stand growth over entire rotations. We applied a modified version of the G’DAY model of carbon, nitrogen and water cycling at a daily time step to short-rotation plantations located in São Paulo State, including a simple mechanistic description of the effect of water availability on growth. The progressive and rapid root exploration of deep soil layers was modeled in a simple way, by considering that maximum plant available water increased with mean tree height. The model was parameterized using detailed measurements made over the entire rotation of an experimental stand of Eucalyptus grandis, and was subsequently applied to 16 clonal stands managed in a similar way by one company, but with different planting dates and contrasting productivity levels. Stem biomass simulations, driven by daily weather data (maximum and minimum air temperatures, global radiation and rainfall), were strongly correlated with company inventory estimates of stem biomass carried out at different ages. The temporal variation of leaf area index was also adequately simulated, as was shown by comparison with leaf area index derived from satellite data. The model was able to capture more than 95% of the variability of standing stem biomass and more than 85% of the variability of stem growth measured on these stands, provided spatial differences in soil water holding capacity were taken into account.