Red Oak Growth Research Articles

High risk, high gain? Trade-offs between growth and resistance to extreme events differ in northern red oak (Quercus rubra L.).

Information about the resistance and adaptive potential of tree species and provenances is needed to select suitable planting material in times of rapidly changing climate conditions. In this study, we evaluate growth responses to climatic fluctuations and extreme events for 12 provenances of northern red oak (Quercus rubra L.) that were tested across three trial sites with distinct environmental conditions in Germany. Six provenances each were sourced from the natural distribution in North America and from introduced stands in Germany. We collected increment cores of 16 trees per provenance and site. Dendroecological methods were used to compare provenance performance and establish climate-growth relationships to identify the main growth limiting factors. To evaluate the provenance response to extreme drought and frost events, three site-specific drought years were selected according to the Standardized Precipitation Evapotranspiration Index (SPEI) and 2010 as a year with an extreme late frost event. Resistance indices for these years were calculated and assessed in relation to overall growth performance. We observed a high variation in growth and in the climate sensitivity between sites depending on the prevailing climatic conditions, as well as a high intra-specific variation. Overall, summer drought and low temperatures in the early growing season appear to constrain the growth of red oak. The resistance of provenances within sites and extreme years showed considerable rank changes and interaction effects. We did not find a trade-off between growth and resistance to late frost, namely, fast growing provenances had a high frost hardiness. Further, there was no evidence for a trade-off between growth and drought hardiness. Still, responses to drought or late frost differ between provenances, pointing to dissimilar adaptive strategies. Provenances from introduced (i.e. German) stands represent suitable seed sources, as they combine a higher growth and frost hardiness compared to their North American counterparts. Drought hardiness was slightly higher in the slow-growing provenances. The results provide a better understanding of the variable adaptive strategies between provenances and help to select suitable planting material for adaptive forest management.

The primary assessment of the red oak seeds quality and prospects for its bioinvasive potential realization in the Samara region urban environment

The world population growth postulates a necessity for food increase to provide mankind with edible products. A growing number of archaeobotanical finds of acorns indicates that they were important as a staple food for some regions. According to its characteristics, red oak is one of the promising species that can increase the resource potential of oak forests in the Middle Volga region. Compared to local oak one, red oak wood is more resistant to vascular and necrotic-cancerous pathologies. The red oak is also more resistant to oak powdery mildew. On the territory of the Middle Volga region, red oak is still rare, because of its limited use in plantations. The subject of the study is the quality of red oak seeds formed by trees from the arboretum of the Institute of Ecology of the Volga Basin (Togliatti city), where they were collected in an amount enough to assess the quality of seeds formed by an introduced species on a territory new to it. The study of the internal structure of oak seeds with dense shells was carried out by digital microfocus radiography using a PRDU installation. This method is included in international standards, primarily for assessing the formation of the seeds internal structure and grain damage by phytophages. X-ray screening allowed to categorize the red oak seeds: 1) seeds, fully formed, filled and not damaged by insects; 2) seeds that, when falling from a tree, retain their cupula (do not have a developed content); 3) seeds damaged by insects during the formation of cotyledons; 4) seeds without a cupula, but with varying severity of underdevelopment; 5) seeds with partial underdevelopment of the cotyledons, which do not fill the entire volume of the seed coats. The weight and size parameters of seeds formed in the Samara region correspond to the indicators from other regions of red oak growth and are: diameter 1,76 0,01 cm; length 2,48 0,02 cm; weight of 1000 seeds 4224 62,65 g (harvest 2021). At the same time, only from 55 to 39% of red oak seeds (harvests in 2021 and 2022, respectively) were of a sufficiently high quality to be used for sowing. Considering the prospects of red oak as an agent of biological invasion, the authors point to the variability of its seed harvest by years, the formation of a high proportion of low-quality seeds, as well as a small amount of self-seedings with increased demands to soil moisture.

Growth of canopy red oak near its northern range limit: current trends, potential drivers, and implications for the future

Red oak (Quercus rubra L.) is projected to expand into the northern hardwood forest over the coming century. We explored the connection between red oak basal area growth and a number of factors (tree age and size, stand dynamics, site elevation, and climate and acid deposition variables) for 213 trees in 11 plots throughout Vermont, USA. Red oak growth generally increased over the course of the chronology (1935–2014) and has been particularly high in recent decades. Growth differed among elevational groups but did not differ between age or size groups. Summer moisture metrics were consistently and positively associated with growth, whereas fall moisture was associated with reduced growth in recent decades. Higher summer temperatures were often negatively associated with growth, though there was evidence that low temperatures in the summer (higher elevations) and fall (lower elevations) constrain growth. Several pollution metrics were associated with reduced growth, a surprising result for a species not known to be sensitive to inputs of acid deposition that have predisposed other species in the region to decline. While red oak growth is currently robust, increases in summer temperatures, reductions in growing season precipitation, or increases in fall precipitation could reduce future growth potential.

Early Tree Growth in Reclaimed Mine Soils in Appalachia USA

Surface mining disturbs hundreds of hectares of land every year in many areas of the world, thereby altering valuable, ecologically-diverse forests. Reforestation of these areas after mining helps to restore ecosystem functions and land value. In Appalachia, native topsoil is normally replaced on the surface during reclamation, but waivers allow for brown and gray sandstone materials to be used as topsoil substitutes. Numerous studies report the growth of trees in these substitute mine soil materials, but few studies have compared the height of trees grown in reclaimed mine soils to the heights of trees grown in native soils. This study determined the growth of red oak (Q. rubra L.), white oak (Quercus alba L.), and tulip poplar (Liriodendron tulipifera L.) in two mine soil types which were compared to projected growth in native soils. Heights of tree seedlings in native soils at 11 years were estimated from site indices (SI) from USDA Soil Survey data. At the mine sites, areas with brown and gray mine soils (one site with a mulch treatment) had 12 tree species planted and growth was measured annually for 11 years. Mine soil pH after 11 years was 5.3 for brown mine soils, 6.6 for gray mine soils, 7.0 for mulched mine soils, and 4.1 to 5.2 for native forest soils. After 11 years, tree heights in gray mine soils were significantly lower (0.5 m) than tree heights in brown mine soils (2.8 to 4 m) for all three species. Trees in mulched mine soils were up to 0.7 m taller than trees in un-mulched brown mine soils. After 11 years, red oak height was 6.3 m in native soils and 3 m in brown and mulched mine soils (52% lower); white oak was 7.3 m tall in native soils compared to 3.6 m in brown mine soils (50% lower); and tulip poplar was 11.5 m tall in native soils and 3.5 to 4 m tall in brown and mulched mine soils (70% lower). In gray mine soils, trees were not growing at all. While the trees in brown mine soils are growing, tree growth has not reached projected levels of tree growth in native soils during the first 11 years after planting. The purpose of forestry reclamation is to restore ecosystem diversity and function. This study showed that one measure of ecosystem function, tree growth, was 50% lower on reclaimed mine soils than native forest soils. Maturing mine soils may develop properties over time that are similar to native soils and, with the increased rooting depth, may provide conditions where increased tree growth rates and height may be attained during the next several decades.

Competition, tree age and size drive the productivity of mixed forests of pedunculate oak, beech and red oak

In order to understand the relationship between tree diversity and forest productivity, it is crucial to understand what is going on at the level of individual trees, since each tree responds to the prevailing environmental conditions and interacts with his neighbours. We explored tree interactions in 53 forest plots in northern Belgium (TREEWEB platform) containing all possible combinations of pedunculate oak, beech and red oak. We cored 307 trees and determined the average annual basal area increment for the last 10 years for each sampled tree. We investigated the importance of neighbourhood competition, tree age an size for tree-level growth and then scaled up the species-specific tree growth to stand-level productivity. By exploring how competition, tree age and size varied along the studied gradient of tree species richness, we were able to explain the observed species-specific tree level and stand-level growth along the tree species richness gradient. We found no relationship between tree species richness and forest productivity, due to contrasting growth patterns of the three species along the richness gradient: the growth of pedunculate oak decreased, growth of beech was constant and growth of red oak increased along the tree species richness gradient. Increased heterospecific competition was the main reason for the observed lower growth of pedunculate oak in mixtures, whereas variation in tree age and size along the studied tree species richness gradient were the main drivers for the observed growth patterns of beech and red oak. Species-specific age differences along the tree species richness gradient could be linked with the species composition. We observed a multi-aged stand structure with the light-demanding pedunculate oak being older than the more shade-tolerant beech and red oak, probably a consequence of management interventions needed to enable long-term coexistence of light-demanding and shade-tolerant species. Our study highlights that the management history of mature forests may influence diversity-productivity relationships and should therefore be taken into account during the analysis.

Riparian buffer growth and soil nitrate supply are affected by tree species selection and black plastic mulching

Tree species selection in the design of agricultural riparian buffers is important to optimize particular ecosystem services, while vegetation management (weed treatment) is often critical in obtaining first-rate tree growth and survival. This farm-scale study took place along a 1km section of a headwater stream in southern Québec (southeastern Canada). Five tree species with contrasted ecological characteristics were planted (Populus×canadensis, Fraxinus pennsylvanica, Quercus macrocarpa, Quercus rubra and Pinus strobus), with black plastic (polyethylene) mulches as the vegetation management method, as well as a control with no vegetation management, all within a fenced herbaceous riparian buffer. Tree growth and survival were measured along with soil nutrient supply. Significant Species×Vegetation treatment interactions where observed for all growth variables (p<0.001), but also for soil nitrate (NO3) supply (p<0.01). All species benefited from the plastic mulch treatment, but varied greatly in their responses. After 5 years, mulched hybrid poplar produced 774 times more stem volume than red oak without mulch. Across all species/vegetation treatment combinations, a 13-fold variation in soil NO3 supply rate was observed during the 4th growing season. Compared to the other species, NO3 supply rate in hybrid poplar plots was 39–87% lower in the plastic mulch treatment and 48–62% lower in the control treatment. Significantly higher soil NO3 supply rates were observed beneath the mulches of non nitrophilous species (white pine and red oak). Red oak growth was negatively correlated with NO3 supply (R2=0.57, p<0.05) in the mulch treatment. Early-successional nitrophilous species (hybrid poplar and red ash) planted with the plastic mulch led to the lowest increase in soil NO3 and the greatest gains in buffer structural attributes (stem volume, diameter and height). Hybrid poplar growth was positively correlated with soil NO3 supply (R2=0.86, p<0.001) in the control treatment. Natural abandoned field/grassland invaders (white pine and bur oak) grew well without black plastic mulch, while the growth of non-mulched red oaks was marginal. In the control treatment, stem volume was a strong negative predictor (across all species) of soil NO3 supply (R2=0.91, p<0.05), indicating that under herbaceous vegetation competition larger trees have a greater ability to reduce soil NO3. This study provides evidence that particular tree species/vegetation management treatment combinations strongly influence early riparian buffer structural development and soil NO3 dynamics in agricultural riparian zones.

What factors influence Quercus rubra growth performance along elevational and exposure gradients

How tree species perform across the breadth of their realized niche is essential for understanding their response to changing environmental conditions. This is especially relevant in topographically heterogeneous landscapes, where changes in elevation, exposure, slope and aspect all interact to determine how a particular species will perform at any location. We focused on growth performance in Quercus rubra (red oak) in Shenandoah National Park. We established 4 transects that spanned &gt;700 meters of elevation change. Each transect encompassed an exposure gradient from a stream-side to a ridgetop location, and were positioned on opposing aspects. Along each transect we cored five mature red oak trees at six equally spaced points. Tree cores were prepared using standard dendroecological methods. Temperature and precipitation data from 1945 to 2016 were obtained from National Climatic Data Center for nine weather stations surrounding Shenandoah National Park. Elevational lapse rates were calculated for temperature data to adjust regional temperature to accurately represent coring locations. Ring width was modelled against climatic and topographic variables to determine which variables were important to red oak growth.Results showed spring and autumn precipitation and temperature from both current and previous year were associated with growth performance. Red oak growth was maximized at low elevations at near to intermediate distances from stream, however as elevation increased red oak performed better at greater distances from streams. As climate continues to warm, higher elevations may receive more precipitation due to evapotranspiration and red oak will be found further from streams at higher elevations.

Invasive glossy buckthorn impedes growth of red oak and sugar maple under-planted in a mature hybrid poplar plantation

Native tree seedlings (nursery produced) were planted under control and herbicide treatments in the understory of a mature hybrid poplar plantation, naturally invaded by glossy buckthorn, a major invasive exotic shrub of Eastern North America. The objectives were to (1) test the negative effect of the invasive buckthorn on seedling growth, (2) determine if this effect differed for two tree species with different shade tolerances and edaphic requirements (sugar maple, red oak), and (3) determine if the type of canopy influenced this effect (5 clones). Confounding factors were reduced in this design (canopy composition and structure, age/size of seedlings), and several factors were controlled (transplantation date, deer exclusion). Several factors were measured (canopy openness, soil nutrients, canopy biomass, understory vegetation biomass, buckthorn density and biomass). After two growing seasons, seedlings of both species had reduced diameter and height increments under buckthorn. This difference was statistically significant for diameter increment. Canopy type did not have any effect on environmental variables or seedling growth. Buckthorn reduced light availability, but had no effect on soil moisture or soil nutrient availability. Consistent with sugar maple’s ecological requirements, its diameter growth was explained (multiple regression) firstly by edaphic variables (positive effect: soil humidity and K), and secondly by buckthorn biomass (negative effect). Red oak growth was explained firstly by buckthorn biomass, and secondly by understory vegetation biomass, both negative effects. Seedlings of species with higher light requirements (red oak) may have large growth reductions under buckthorn cover and have difficulty overtopping it. These results indicate that under-planting (plantations, forests) or afforestation should occur rapidly after buckthorn removal, otherwise this introduced invasive shrub may greatly reduce survival and growth of planted trees. Restoration of red oak to areas of former abundance will likely be more difficult because of the competition from glossy buckthorn.

Loss of Neighbors, Fire, and Climate Effects on Texas Red Oak Growth in a Juniper-dominated Woodland Ecosystem

In this study, we assessed growth response of Quercus buckleyi (Texas red oak), a current codominant deciduous oak species in central Texas woodlands, to changes in competition, fire, and climate over time to evaluate factors related to documented regional decline of this species. For this analysis, we collected 372 tree slabs of Texas red oaks from the woodlands of the Balcones Canyonlands National Wildlife Refuge near Austin, Texas, from which we aged fire scars and measured tree-ring widths to calculate basal area increment and ring-width indices. To determine canopy conditions of these trees over time, we used historical aerial photos from 1937 to 2004 acquired approximately every 15 y to evaluate changes in woody vegetation cover for the locations of the trees sampled. Our results showed that trees affected by loss of local woody vegetation cover, as evaluated by the aerial photographs, and fire had higher average basal area increment than trees without fire evidence and loss of cover. These differences were significant when aspect and slope were added to the analysis. For climate, we found significant correlation between annual Palmer Drought Severity Indices and ring-width indices for the time interval of 1937–1978, but not after, indicative of potential recent decoupling between tree-ring changes and climate. We found drought to potentially be a major driver of community change in this system as it affects tree-ring response, fire, and mortality assessed from sampled trees.

English

The invasion of Tree-of-Heaven (Ailanthus altissima) has been documented in disturbed landscapes leading to biodiversity loss and degradation of ecosystem function. Ailanthus interferes with the restoration of native species by its aggressive growth habit, alteration of nutrient cycles, and allelopathic chemical production. Recent studies suggest that allelopathy has a negative effect on the growth of red oak (Quercus rubra), possibly by interfering with the symbiosis of beneficial ectomycorrhizal fungi (ECM). This fungal symbiont is essential for healthy tree growth and the unavailability of these fungi may impede the success of seedling regeneration. This study investigated the effects of Ailanthus on biomass production and ectomycorrhizal fungal (ECM) colonization of red oak (Q. rubra) seedlings on a reclaimed coal mine site in eastern Ohio. Six plots were designated in an existing riparian buffer zone in a wetland at The Wilds Conservation Center in Muskingum County. Three of the plots were in an area where mature Ailanthus was present. The other three plots were located in the same riparian zone that was without Ailanthus. Naturally regenerating two- year-old red oak seedlings were selected for study (10 seedlings per plot, 60 seedlings total). The oak seedlings were sampled for biomass (g) and ECM root colonization. Two-year-old oak seedlings growing among mature Tree-of- Heaven produced significantly less biomass, specifically in root production, than the oaks growing without the invasive tree (P = 0.02). There was a decrease in ECM colonization (P = 0.001) and a shift in ECM community composition in plots where the Tree-of-Heaven was present (P = 0.0004). The increase in root biomass and ECM colonization may aid in the plant's competitive ability for belowground resources, important for reestablishment. These data suggest that areas impacted by the invasion of Tree-of-Heaven may require restoration with plant species less reliant on ECM colonization when planting in soils immediately following invasive species removal.

Five-year radial growth of red oaks in mixed bottomland hardwood stands

We studied the relationships among 5-year radial (diameter and basal area) growth of red oak (genus Quercus, subgenus Erythrobalanus) crop trees and predictor variables representing individual tree vigor, distance-dependant competition measures, and distance-independent competition measures. The red oaks we examined are representative of the commercially and ecologically important oak species of the bottomland hardwood forests of the southeastern US. The crown class score, a quantitative measure of crown class and tree vigor, performed best in accounting for the variability in tree diameter growth. Plot-level variables failed to account for a significant proportion of the variability in tree radial growth. The basal area of the first-order neighbors that were taller than the crop trees and located within 2.4 times the mean overstory crown radius had the highest negative correlation with crop tree 5-year radial growth. Red oaks were a major part of these competitors and likely exerted the greatest competitive pressure. However, crop tree radial growth was positively associated with the basal area of the red oaks which were indirect (second order) neighbors and which were taller than the crop trees. It is possible that indirect neighbors do not compete with the crop trees, but they likely compete with the direct competitors of the crop trees, thus having an indirect positive influence on crop tree growth. Such reasoning is consistent with previously observed spatial dependence up to four times the mean overstory crown radius. The findings may have implications for thinning hardwoods stands and crop tree management in that foresters need to take into account (1) oak intra-genus competition, (2) the negative competitive effect of direct neighbors, and (3) the potentially positive effect of the indirect neighbors, the competitors’ competitors.

ATMOSPHERIC DEPOSITION MAY AFFECT NORTHERN HARDWOOD FOREST COMPOSITION BY ALTERING SOIL NUTRIENT SUPPLY

In the northeastern United States, the input of reactive nitrogen (N) via atmospheric deposition has increased rapidly since the onset of the industrial revolution. During the same period of time, acid precipitation and forest harvest have removed substantial quantities of base cations from soil. Because of the dominance of base-poor soils and the low rates of atmospheric base cation deposition, soils throughout the northeastern United States may be increasingly rich in N but poor in calcium (Ca). We studied the consequences of a change in soil N and Ca availability on forest composition by transplanting seedlings of four tree species into replicate plots in the understory and in canopy gaps amended with N and Ca in factorial combination. In this paper, we report on the growth and survivorship of seedlings over a four-year period. Relative to control plots, fertilization with N increased red maple growth by an average of 39% whereas fertilization with Ca decreased survivorship in the understory by 41%. In sugar maple, fertilization with Ca increased growth by 232% and 46% in the forest understory and in canopy gaps, respectively, and significantly increased high light survivorship. Fertilization with N decreased white pine survivorship by 69% in the understory whereas high Ca availability significantly increased survivorship. Fertilization with N or Ca alone reduced red oak growth but had no effect on survivorship. The results of this study suggest that historical losses of soil Ca and the continuing effects of atmospheric-N deposition on N availability are likely to alter the composition of northeastern North American forests because of the positive effects of N enrichment on the growth of red maple and the negative effects of Ca loss on the growth and survivorship of sugar maple and white pine.

TRANSPLANTING AND ORGANIC MULCH AFFECT GAS EXCHANGE AND GROWTH OF FIELD GROWN RED OAK (QUERCUS SHUMARDII BUCKLI.)

Balled in burlaped is a common method for moving large trees into landscapes and affects of transplanting on tree gas exchange and growth has been documented. Organic mulch provides many benefits and is often recommended for landscapes. Because little research has been conducted on affects organic mulch has on gas exchange and growth of transplanted and non-transplanted trees, this research investigated the effects transplanting and organic mulch have on gas exchange and growth of field grown red oak (Quercus shumardii) trees. In March 2003, 12 multi-trunked trees were selected from a tree farm near Lubbock, Texas, and six trees were dug using a tree spade and placed in their original location. Mulch at a depth of 10 cm was placed around the rootball of 3 transplanted and 3 nontransplanted trees and maintained at this depth the remainder of the experiment. Over the next three growing seasons predawn leaf water potential and midday stomatal conductance were measured on each tree every 1 to 3 weeks. At the end of every growing season shoot elongation, stem caliper and subsample leaf area were recorded. Our data indicates transplanting has a negative affect on gas exchange and growth of red oak. Each growing season gas exchange, shoot growth, and subsample leaf area were less for transplanted trees when compared to nontransplanted trees. Mulch also influenced gas exchange and growth of these trees. For nontransplanted trees with mulch, gas exchange and growth were reduced when compared to nonmulched, nontransplanted trees. For transplanted trees with mulch, predawn leaf water potential was less negative and subsample leaf area was greater when compared to transplanted trees with out mulch.

THE INFLUENCE OF BIOSTIMULANTS ON GROWTH AND VITALITY OF THREE URBAN TREE SPECIES FOLLOWING TRANSPLANTING

Summary Four commercially available, biostimulants sold under the trade names ‘Generate’, ‘Crop Set’, ‘Fulcrum’ and ‘Redicrop 2000’ were applied either as a root drench or foliar spray to three transplant-sensitive tree species, red oak(Quercus rubra), birch(Betula pendula) and beech (Fagus sylvatica) post transplanting. The short and long-term efficacy of the biostimulants on growth was quantified by recording root and shoot vigour at week 8 and 20. In addition, improvements in tree vitality were assessed by measurement of a chlorophyll a performance index based on leaf chlorophyll fluorescence emissions. Irrespective of species, no significant effect of mode of application (foliar spray versus root drench) was recorded on growth and vitality. The biostimulants Generate and Fulcrum increased growth of all three tree species. No significant effects on growth and chlorophyll fluorescence of birch and beech were recorded following applications of the biostimulants Crop Set and Redicrop 2000, however, significant increase in growth of red oak was recorded. Only the biostimulant Generate increased chlorophyll fluorescence values of all test species. Results show use of biostimulants can improve root and shoot vigour following transplanting. However, selection of an appropriate biostimulant is critical as effects on growth and vitality can vary widely between tree species possibly as a result of the differing active ingredient used in the formulation of the product.

Improving hardwood afforestation success: an analysis of the effects of soil properties in southwestern Quebec

Seven hardwood tree species, planted over five different soil types on abandoned farmland sites of southwestern Quebec, and free of competition for light and soil resources, are assessed (at 7 years) in order to identify soil properties associated with their successful establishment and growth. Best red oak and bur oak “live stem growth” (height or diameter of surviving trees only) occurred on soils derived from non-dolomitic parent material (less alkaline). “Total red oak growth” (height or diameter weighted to include mortality effect by dividing by initial number of trees) was reduced with higher soil water content. Mean soil water content was positively associated to live stem growth of red ash and black walnut, and negatively related to total white ash growth. Analyses of white ash also indicated that highest “total tree diameter” (diameter weighted to include mortality) was positively associated with soil nitrification. Best white ash growth was attained where lower foliar concentrations of nitrogen and phosphorus were measured, thus raising the question of long term growth advantage on these soils. High soil nitrogen mineralization was important in producing high mean live stem growth of black walnut and butternut. Species which can maximize productivity on each soil type were identified to improve afforestation success on former farmland.

Ca:Al Ratio Effects on Growth and Competitive Interactions of Northern Red Oak (Quercus rubra) and Yellow-Poplar (Liriodendron tulipifera)

in yellow-poplar; leaf [N] was significantly higher in red oaks grown at Ca:Al of 4 than 100. Yellow-poplar grew better in interspecific pairs than in intraspecific pairs. In contrast, competitive mode had no effect on red oak growth. Analysis of soil N pools indicated that red oak was unable to make use of the inorganic N added during biweekly nutrient solution additions. In contrast yellow-poplar was able to deplete soil N pools rapidly and its growth was probably N limited at Ca:Al ratio of 100. The critical Ca:Al threshold for growth decline appeared to be 4.0 for yellow-poplar. Yellow-poplar outcompetes red oak under N enriched conditions, but its competitive advantage decreases at lowered Ca:Al ratio. We hypothesize that the current shift in tree species composition observed in eastern North America may be the consequence of N enrichment, but that the direction of these shifts may reverse as lowered Ca:Al ratio and other effects of N saturation develop.

SHORT RANGE SOIL VARIABILITY AND ITS EFFECT ON RED OAK GROWTH (QUERCUS RUBRA L.)

La variabilite spatiale des proprietes du sol est etudiee sur une surface de 1,93 ha plantee uniquement de chenes rouges âges de 15 ans et situee en Dordogne (France). La variabilite de la croissance du chene rouge semble pouvoir etre due a une variabilite de 2 proprietes majeures du sol : profondeur de la roche mere et profondeur des carbonates. Une approche geostatistique est utilisee pour analyser la structure spatiale de ces 2 caracteristiques

Effect of Seedling Age and Taproot Length on Performance of Oak

Abstract White oak and northern red oak seedlings were planted in an old field site in Indiana and evaluated for 9 yr to determine if seedling age and initial taproot length affected growth performance. Both 1-0 and 2-0 seedlings were produced in specially designed containerized seedbeds that provided for root pruning to lengths of 23 and 30 cm through control of the level of water saturation in the rooting medium. Survival of both species was high, 95%-100%. Northern red oak growth was not significantly influenced by initial seedling age or taproot length. White oak, however, performed the best when seedlings were 2 yr old and had a 30 cm long taproot. Seedling age was the more important factor affecting growth. North. J. Appl. For. 10(4):175-178.

Predicting Post-Harvest Performance of Advance Red Oak Reproduction in the Southern Appalachians

Abstract Models are presented for predicting: (1) height growth of red oak advance reproduction after clearcutting, and (2) the probability of stems becoming dominants or codominants in new stands as a function of preharvest size of advance reproduction and site quality. The second model permits silviculturists to predict, prior to harvest, the contribution to a new stand of an existing population of advance red oak reproduction. For. Sci. 36(4):908-916.

Tolerance of Red Oak and American and European Beech Seedlings to Aluminum

AbstractThe effect of aluminum (Al) on the growth of red oak (Quercus rubra L.), American beech (Fagus grandifolia Ehrh.), and European beech (Fagus sylvatica L.) seedlings was studied in solution culture containing from 0 to 3000 µM Al at pH 4.0. Aluminum had no detrimental effect on biomass of shoots of red oak and American beech. Shoot biomass of European beech was significantly reduced by Al, with greater reductions measured for seedlings grown in lower ionic‐strength media. Root biomass of species did not decline with increasing Al, and actually increased in some Al treatments. Generally, Ca, Mg, and P tissue concentrations of leaves and roots decreased with increasing solution Al for all three species. Even at the lowest solution Al concentration, 500 µM, significant reductions relative to the controls were measured. Of the elements measured, P appeared to be the most strongly correlated with shoot biomass response, having r values of 0.87 and 0.98 for American beech and European beech, respectively. Results from these studies indicate that the risk of direct effects of toxic soil solution Al concentrations on growth of red oak and American beech seedlings is low. However, soil solution concentrations of 500 µM have been reported in Europe and these correspond to the Al level found to significantly reduce shoot biomass of European beech in this study.