Predicting site index from climatic, edaphic, and stand structural properties for seven plantation-grown conifer species in Quebec

2011 ◽  
Vol 41 (4) ◽  
pp. 682-693 ◽  
Author(s):  
Jean Beaulieu ◽  
Frédéric Raulier ◽  
Guy Prégent ◽  
Jean Bousquet
Keyword(s):  
Stand Structure ◽  
Vapour Pressure Deficit ◽  
Summer Precipitation ◽  
Site Index ◽  
Height Distribution ◽  
Degree Days ◽  
Conifer Species ◽  
Reduced Models ◽  
Plantation Yield ◽  
Water Holding

Models were built to relate site index to biophysical variables and stand structure for seven conifer species grown in plantation. Reduced models without stand structure were also derived to allow the prediction of site index even when information on the stand is unavailable. Biophysical variables tested were degree-days, aridity, summer precipitation, vapour pressure deficit, and soil water-holding capacity. The stand structure was accounted for using a Shannon evenness index of diameter at breast height distribution. Both full and reduced models had low to moderate R2 values and were slightly biased for most of the species. The results indicate that while correlations between phytometric and biophysical site indices are rather weak, those between plantation yield predicted using both indices and volume observed in the field are reasonably high (above 0.80). The biophysical site index models derived in this study could be used for strategic planning to estimate plantation yield or allowable cut for each of the seven conifer species.

scholarly journals Stand density biases the estimation of the site index especially on dry sites

2020 ◽  
Author(s):  
Astor Toraño Caicoya ◽  
Hans Pretzsch
Keyword(s):  
Norway Spruce ◽  
Stand Structure ◽  
Local Density ◽  
Generalized Additive Models ◽  
Stand Density ◽  
Moisture Stress ◽  
Site Index ◽  
Additive Models ◽  
Climate Conditions ◽  
Density Control

The Site Index (SI) has been widely used in forest management and silviculture. It relies on the assumption that the height of dominant trees in a stand is independent from the local density. However, research on climate change suggests that under certain moisture stress conditions, this may not hold. Here, based on 29 plots from 5 long-term research experiments, we have tested the effect of local stand density on the SI of Norway spruce (Picea abies (L.) H. Karst). With generalized additive models (GAMM), we analyzed the effect of stand structure and climate predictors on SI. The two evaluated models revealed that local stand density and age had a significant effect on SI (p≤0.001 ), showing a clear negative trend especially significant on sites with poor and dry soils, which may reduce the site index by a maximum of approximately 4 m for an increase in density between 400 and 600 trees/ha. We stress that the physiological characteristics of Norway spruce, flat-rooting system and xeromorphism, especially when growing in pure stands, may explain these effects. Thus, density control and growth in mixtures may help to reduce the water stress and losses in height growth under future climate conditions.

scholarly journals Dendrochronological analysis and growth patterns of Polylepis reticulata (Rosaceae) in the Ecuadorian Andes

IAWA Journal ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 331-S5 ◽  
Author(s):  
C. Alvites ◽  
G. Battipaglia ◽  
G. Santopuoli ◽  
H. Hampel ◽  
R.F. Vázquez ◽  
...  
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Stand Structure ◽  
Climatic Factors ◽  
Southern Oscillation ◽  
Ring Width ◽  
Vapour Pressure Deficit ◽  
Growth Patterns ◽  
Tree Ring Width ◽  
Sources Of Information

ABSTRACTRelict tree species in the Andean mountains are important sources of information about climate variability and climate change. This study deals with dendroclimatology and growth patterns in Polylepis reticulata Hieron., growing at high elevation (mean of 4000 m a.s.l.) in three sites of the Ecuadorian Andes. The aims of the research were: (i) characterizing tree-ring boundaries; (ii) describing tree-ring patterns of the study sites; (iii) investigating the relationships between climate and radial tree growth; and (iv) determining the spatial correlation between seasonal climatic factors and tree-ring width of P. reticulata. Tree rings were characterized by semi-ring porosity and slight differences in fibre wall thickness between latewood and subsequent earlywood. In all sampling sites, tree rings in heartwood were more clearly visible than in sapwood. Tree-ring width was more related to temperature than to precipitation, with growth being also affected by site conditions and stand structure, as well as other local factors. No significant relationships were found between tree-ring chronologies of P. reticulata and El Niño-Southern Oscillation (ENSO) and Vapour Pressure Deficit indices. The study highlights that there is not a clear driving climate factor for radial growth of P. reticulata. Additional research is needed to study growth dynamics of this species and the impacts of local environmental variables.

Site Quality Evaluation Models for Aspen (Populustremuloides Michx.) in Wisconsin

1975 ◽  
Vol 5 (4) ◽  
pp. 523-528 ◽  
Author(s):  
James S. Fralish ◽  
Orie L. Loucks
Keyword(s):  
Site Index ◽  
Water Holding Capacity ◽  
Site Quality ◽  
Quaking Aspen ◽  
North Central ◽  
Available Water ◽  
Soil Calcium ◽  
Calcium Magnesium ◽  
Regression Techniques ◽  
Water Holding

Soil and site relationships were studied in 32 mature quaking aspen (Populustremuloides Michx.) communities in north central Wisconsin. Multiple linear regression techniques indicated that soil texture, available water-holding capacity, water-table depth, and stand exposure were the most important factors controlling site index. Two models developed from combinations of these factors accounted for 62% of the variation in site index. Values for soil calcium, magnesium, potassium, and phosphorus were corrected for bulk density and summed to 12-, 24-, 36-, and 60-in. depths. When included in additional models, only magnesium to a 60-in. depth was found to have additional effect on aspen growth over and above that implicit in available water-holding capacity. The models were validated using 10 additional mature aspen stands and then applied to data from 10 stands in early stages of deterioration.

scholarly journals Response of temperate grasslands at different altitudes to simulated summer drought differed but scaled with annual precipitation

2009 ◽  
Vol 6 (11) ◽  
pp. 2525-2539 ◽  
Author(s):  
A. K. Gilgen ◽  
N. Buchmann
Keyword(s):  
Stand Structure ◽  
Management Strategies ◽  
Summer Precipitation ◽  
Biomass Productivity ◽  
Annual Precipitation ◽  
Summer Drought ◽  
Weed Species ◽  
Vegetation Height ◽  
Ground Biomass ◽  
Below Ground

Abstract. Water is an important resource for plant life. Since climate scenarios for Switzerland predict an average reduction of 20% in summer precipitation until 2070, understanding ecosystem responses to water shortage, e.g. in terms of plant productivity, is of major concern. Thus, we tested the effects of simulated summer drought on three managed grasslands along an altitudinal gradient in Switzerland from 2005 to 2007, representing typical management intensities at the respective altitude. We assessed the effects of experimental drought on above- and below-ground productivity, stand structure (LAI and vegetation height) and resource use (carbon and water). Responses of community above-ground productivity to reduced precipitation input differed among the three sites but scaled positively with total annual precipitation at the sites (R2=0.85). Annual community above-ground biomass productivity was significantly reduced by summer drought at the alpine site receiving the least amount of annual precipitation, while no significant decrease (rather an increase) was observed at the pre-alpine site receiving highest precipitation amounts in all three years. At the lowland site (intermediate precipitation sums), biomass productivity significantly decreased in response to drought only in the third year, after showing increased abundance of a drought tolerant weed species in the second year. No significant change in below-ground biomass productivity was observed at any of the sites in response to simulated summer drought. However, vegetation carbon isotope ratios increased under drought conditions, indicating an increase in water use efficiency. We conclude that there is no general drought response of Swiss grasslands, but that sites with lower annual precipitation seem to be more vulnerable to summer drought than sites with higher annual precipitation, and thus site-specific adaptation of management strategies will be needed, especially in regions with low annual precipitation.

scholarly journals Relative Roles of Large-Scale Orography and Land Surface Processes in the Global Hydroclimate. Part II: Impacts on Hydroclimate over Eurasia

2006 ◽  
Vol 7 (4) ◽  
pp. 642-659 ◽  
Author(s):  
Kazuyuki Saito ◽  
Tetsuzo Yasunari ◽  
Kumiko Takata
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Warm Season ◽  
Summer Precipitation ◽  
Winter Precipitation ◽  
Bare Rock ◽  
Surface Scheme ◽  
Water Holding ◽  
East West ◽  
Higher Sensitivity

Abstract A series of simplistic simulations from an AGCM coupled to a simple land surface scheme and water vapor tracers was performed to explore the relative roles of basic factors in land surface conditions, with regard to the seasonal evolution of the hydroclimate over Eurasia. Large-scale orography in Asia and vegetation (further decomposed to soil and vegetation skin) were evaluated, with orography represented in the model by surface altitude, soil represented by water-holding capacity, and vegetation skin represented by surface albedo and roughness. The percentage of global annual precipitation over land (occupying 25.6% of the total surface) was 14.8%, 15.0%, and 21.7% for the mountainless “bare rock” (i.e., vegetationless) surface, and the bare-rock and vegetated surface, respectively. The result for evaporation was 8.9%, 9.0%, and 16.2%, respectively, showing higher sensitivity to the land surface changes than precipitation. The orography and vegetation (i.e., soil and vegetation skin) showed different impacts on Eurasian hydroclimate on the seasonal and regional scales. Thermodynamical forcings to the atmosphere increased over the continent with the inclusion of both. Large-scale orography in Asia exerted east–west contrast in the surface energy exchange in summer in eastern Eurasia. An increase in extratropical winter precipitation with mountains was also noticed because of the atmospheric vapor transport changes. Impact of soil and vegetation skin was clearly found in the warm season in the extratropics; soil impacts extratropical summer precipitation due to enhanced recycling of water and the resultant increased water supply.

scholarly journals Simulating Multiaged Coast Redwood Stand Development: Interactions between Regeneration, Structure, and Productivity

2009 ◽  
Vol 24 (1) ◽  
pp. 24-32 ◽  
Author(s):  
John-Pascal Berrill ◽  
Kevin L. O'Hara
Keyword(s):  
Stand Structure ◽  
Basal Area ◽  
Stand Density ◽  
Site Index ◽  
Growth And Yield ◽  
Stand Development ◽  
Area Index ◽  
Coast Redwood ◽  
Stand Growth ◽  
Upper Limit

Abstract Multiaged management regimes and harvesting scenarios were simulated in coast redwood (Sequoia sempervirens [D. Don.] Endl.) stands using models of stand growth and yield (CRYPTOS) and stocking assessment (redwood MASAM). Various stocking and age-class combinations were modeled on site index 100 and 130 ft (50 years). Results demonstrated how the number of cohorts, upper limit of stocking, and cohort densities affected growth and yield. Board foot volume increment reached a plateau in stands with a prescribed upper limit of stocking above leaf area index 7.2 to 8.6. Productivity did not differ between stands with two to five cohorts producing the same tree size at harvest. It was affected by stand structure when a cutting cycle of 20 years was prescribed in stands with three to five cohorts. Stands with the same density returned to the upper limit of stocking much sooner on better sites. Prolonging the cutting cycle by reducing stand density resulted in larger tree sizes at harvest and greater productivity. The growth of trees remaining after cutting 10–50% of stand basal area and growth of new stump sprouts were also simulated. Stands quickly returned to preharvest stocking after light cutting, implying that heavy or frequent light cutting is needed to sustain growth and vigor of regeneration in multiaged coast redwood stands.

scholarly journals Response of temperate grasslands at different altitudes to simulated summer drought differed but scaled with annual precipitation

2009 ◽  
Vol 6 (3) ◽  
pp. 5217-5250 ◽  
Author(s):  
A. K. Gilgen ◽  
N. Buchmann
Keyword(s):  
Stand Structure ◽  
Summer Precipitation ◽  
Biomass Productivity ◽  
Annual Precipitation ◽  
Summer Drought ◽  
Weed Species ◽  
Adaptation Measures ◽  
Vegetation Height ◽  
Ground Biomass ◽  
Below Ground

Abstract. Water is an important resource for plant live. Since climate scenarios for Switzerland predict an average reduction of 20% in summer precipitation until 2070, understanding ecosystem responses to water shortage, e.g. in terms of plant productivity, is of major concern. Thus, we tested the effects of simulated summer drought on three managed grasslands along an altitudinal gradient in Switzerland from 2005 to 2007, representing typical management intensities at the respective altitude. We assessed the effects of drought on above- and below-ground productivity, stand structure (LAI and vegetation height) and resource use (carbon and water). Drought responses of community above-ground productivity differed among the three sites but scaled positively with total annual precipitation at the sites (R2=0.85). Annual community above-ground biomass productivity was significantly reduced by summer drought at the alpine site receiving the least amount of annual precipitation, while no significant decrease (rather an increase) was observed at the pre-alpine site receiving highest precipitation amounts in all three years. At the lowland site (intermediate precipitation sums), biomass productivity significantly decreased in response to drought only in the third year, after showing increased abundance of a drought tolerant weed species in the second year. No significant change in below-ground biomass productivity was observed at any of the sites in response to simulated summer drought. However, community carbon isotope ratios increased under drought conditions, indicating an increase in water use efficiency. We conclude that there is no general drought response of Swiss grasslands, but that sites with lower annual precipitation seem to be more vulnerable to summer drought than sites with higher annual precipitation, and thus site-specific adaptation measures will be needed especially in regions with low annual precipitation.

Stand dynamics of mixed red alder – conifer forests of southeast Alaska

2004 ◽  
Vol 34 (4) ◽  
pp. 969-980 ◽  
Author(s):  
Robert L Deal ◽  
Paul E Hennon ◽  
Ewa H Orlikowska ◽  
David V D'Amore
Keyword(s):  
Stand Structure ◽  
Large Diameter ◽  
Basal Area ◽  
Height Growth ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Conifer Forests ◽  
Red Alder ◽  
Southeast Alaska ◽  
Dead Trees

Stand structure and dynamics were evaluated in mixed red alder (Alnus rubra Bong.) – conifer forests of southeast Alaska. We assessed stand development, tree density, total basal area, diameter distribution of live and dead trees, height distribution of live trees, and mean diameter of all and largest conifers in 40-year-old red alder – conifer stands that developed following logging. Forty-five plots were established in nine stands sampled across a com po si tional range of 0%–86% alder. Alder height growth was initially rapid then slowed considerably, whereas conifer height growth was initially slow then rapidly increased with conifers now being 4–9 m taller than associated alders. Most alder diameters were 20–30 cm and conifer diameters were more variable with numerous small (3–10 cm) and a few large (>25 cm) trees. Total stand basal area significantly decreased (p = 0.013) with increasing proportions of alder, but density of live and dead trees was not closely associated with alder composition. More than 60% of all dead trees died standing regardless of size or species. Overall, these mixed red alder – conifer stands provided more heterogeneous structures than pure conifer stands, with more even diameter distributions, multiple canopy layers, and similar numbers of large diameter conifers.

scholarly journals Development and evaluation of a biomass increment based index for site productivity

2017 ◽  
Vol 47 (3) ◽  
pp. 400-410 ◽  
Author(s):  
Chris Hennigar ◽  
Aaron Weiskittel ◽  
H. Lee Allen ◽  
David A. MacLean
Keyword(s):  
Prince Edward Island ◽  
Stand Structure ◽  
Abies Balsamea ◽  
Growth Index ◽  
Tree Height ◽  
Predictive Performance ◽  
Forest Productivity ◽  
Site Index ◽  
Future Research ◽  
Biomass Growth

Measures of forest productivity generally rely on site index, which can be problematic for multicohort and mixed-species stands. Using stand growth and dominant tree height–age (i.e., site tree) measurements from ∼10 900 plot locations from Maine, Nova Scotia, New Brunswick, and Prince Edward Island, a forest productivity model for the Acadian Forest Region was developed as a function of climate, lithology, soils, and topographic metrics. Approximately 65% of variation in observed aboveground dry-biomass growth rate (BG) was explained by a Chapman–Richards function of temperature, bedrock, soil root space, slope, and depth to water in combination with stand structure and species predictors. Productivity was then defined in terms of the predicted asymptote of BG, holding structure and species constant, which was termed biomass growth index (BGI), i.e., the site-influenced component of the BG relationship. BGI was mapped on a 20 m grid throughout the region. BGI explained 0%–30% of the variability in spruce (Picea sp.) and balsam fir (Abies balsamea (L.) Mill.) site index and had similar site index predictive performance (±5%) when compared with existing land productivity classifications in each province. BGI provides a direct relationship between site variables and growth and can help guide forest management decisions and future research.

scholarly journals Adaptation to climate change: Genetic variation is both a short- and a long-term solution

2005 ◽  
Vol 81 (5) ◽  
pp. 704-709 ◽  
Author(s):  
Jean Beaulieu ◽  
André Rainville
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
White Spruce ◽  
Site Index ◽  
Seed Source ◽  
Transfer Model ◽  
Index Model ◽  
Seed Sources ◽  
Site Index Model ◽  
Plantation Yield

We propose a methodology combining a biophysical site index model and a seed source transfer model based on both temperature and precipitation to estimate white spruce plantation yield under present and future global warming conditions. The biophysical site index model predicts dominant height at 25 years, which is further used to estimate plantation yield using yield tables. The transfer model shows that, on average, seed sources are best adapted to the temperature conditions where they presently grow, and give maximum yield under these conditions. However, this model also shows that transfer of seed sources to drier sites could improve plantation yield. To predict site index values under climate change conditions, values obtained from the biophysical site index model are corrected by a factor estimated using the seed source transfer model. Our simulation results predict that global warming should favour a slight increase in white spruce plantation yield in southern Québec. However, one cannot expect to obtain similar yields from a seed source rapidly exposed to warmer conditions compared with a seed source that is presently growing under climatic conditions to which it has become adapted. It would take several generations (adaptation lag) for a seed source to adapt to warmer conditions. We believe that the method we propose will be helpful in identifying the most productive seed source to be used at any given location in the province, and in revising seed source transfer rules. Key words: climate change, white spruce, provenance test, transfer model, site index, adaptation, plantation, GIS

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