A basal area increment model for individual trees growing in even- and uneven-aged forest stands in Austria

1996 ◽  
Vol 80 (1-3) ◽  
pp. 57-80 ◽  
Author(s):  
Robert A. Monserud ◽  
Hubert Sterba
2018 ◽  
Vol 31 (1) ◽  
pp. 99-106
Author(s):  
Nishtman Hatami ◽  
Peter Lohmander ◽  
Mohammad Hadi Moayeri ◽  
Soleiman Mohammadi Limaei

2018 ◽  
Vol 10 (5) ◽  
pp. 198 ◽  
Author(s):  
Emanuel Arnoni Costa ◽  
César Augusto Guimarães Finger ◽  
André Felipe Hess

Models that report the effect of competition are important for forest management since forests with higher levels of competition have lower increment rates, and their use is necessary to plan forest interventions. Thus, this study aimed to assess the effect of competition in the basal area increment of individual trees of Araucaria angustifolia (Bertol.) Kuntze in a natural forest. A total of 397 subject trees were measured, covering the diametric range. The dendrometric and morphometric characteristics of subject trees and their competitors were obtained, and 22 distance-dependent and distance-independent competition indices were calculated, in addition to increment cores extracted radially from the trunk at diameter at breast height. The relationship between models of periodic annual increment in basal area based on competition indices has allowed to obtain R2 values of 0.425 and Syx% ≥ 50.2. The multivariate technique of principal component analysis has shown that three principal components explain 78.43% of total variation. The first component was responsible for explaining 52.95%, with similar eigenvector for 11 competition indices, evidencing that these models can be used to describe especies competition, although they show different variables and mathematical equations in calculations. Results show the importance of competition to predict increment of Araucaria in individual trees.


1980 ◽  
Vol 10 (1) ◽  
pp. 71-77 ◽  
Author(s):  
P. W. West

Growth of diameter of individual trees can be expressed as diameter increment or basal area increment. Little work has been done to determine which of these parameters is preferable for use in growth studies. This paper examines growth of trees in pure and mixed stands of even-aged, regrowth forest of Eucalyptusregnans, E. obliqua, and E. globulus, aged 6-80 years, thinned and unthinned, in southeastern Tasmania. Weighted least squares regression equations are developed to relate diameter and basal area increments, over 1- to 6-year increment periods, to initial tree diameter in 29 growth plots. The correlation between basal area increment and initial diameter was always greater than that between diameter increment and initial diameter in these relationships. Despite this, the precision of estimates of future diameter in each plot is shown to be the same whether diameter or basal area increment equations are used. Data from a thinning experiment in 38- to 85-year-old, even-aged Acersaccharum, Fraxinusamericana, and Prunusserotina stands in southern Ontario are also examined and similar results obtained. It is concluded that no apriori reason exists for expressing growth as diameter increment or basal area increment in studies of these types.


2021 ◽  
Vol 13 (12) ◽  
pp. 2297
Author(s):  
Jonathon J. Donager ◽  
Andrew J. Sánchez Meador ◽  
Ryan C. Blackburn

Applications of lidar in ecosystem conservation and management continue to expand as technology has rapidly evolved. An accounting of relative accuracy and errors among lidar platforms within a range of forest types and structural configurations was needed. Within a ponderosa pine forest in northern Arizona, we compare vegetation attributes at the tree-, plot-, and stand-scales derived from three lidar platforms: fixed-wing airborne (ALS), fixed-location terrestrial (TLS), and hand-held mobile laser scanning (MLS). We present a methodology to segment individual trees from TLS and MLS datasets, incorporating eigen-value and density metrics to locate trees, then assigning point returns to trees using a graph-theory shortest-path approach. Overall, we found MLS consistently provided more accurate structural metrics at the tree- (e.g., mean absolute error for DBH in cm was 4.8, 5.0, and 9.1 for MLS, TLS and ALS, respectively) and plot-scale (e.g., R2 for field observed and lidar-derived basal area, m2 ha−1, was 0.986, 0.974, and 0.851 for MLS, TLS, and ALS, respectively) as compared to ALS and TLS. While TLS data produced estimates similar to MLS, attributes derived from TLS often underpredicted structural values due to occlusion. Additionally, ALS data provided accurate estimates of tree height for larger trees, yet consistently missed and underpredicted small trees (≤35 cm). MLS produced accurate estimates of canopy cover and landscape metrics up to 50 m from plot center. TLS tended to underpredict both canopy cover and patch metrics with constant bias due to occlusion. Taking full advantage of minimal occlusion effects, MLS data consistently provided the best individual tree and plot-based metrics, with ALS providing the best estimates for volume, biomass, and canopy cover. Overall, we found MLS data logistically simple, quickly acquirable, and accurate for small area inventories, assessments, and monitoring activities. We suggest further work exploring the active use of MLS for forest monitoring and inventory.


2015 ◽  
Vol 166 (6) ◽  
pp. 380-388 ◽  
Author(s):  
Pascale Weber ◽  
Caroline Heiri ◽  
Mathieu Lévesque ◽  
Tanja Sanders ◽  
Volodymyr Trotsiuk ◽  
...  

Growth potential and climate sensitivity of tree species in the ecogram for the colline and submontane zone In forestry practice a large amount of empirical knowledge exists about the productivity of individual tree species in relation to site properties. However, so far, only few scientific studies have investigated the influence of soil properties on the growth potential of various tree species along gradients of soil water as well as nutrient availability. Thus, there is a research gap to estimate the productivity and climate sensitivity of tree species under climate change, especially regarding productive sites and forest ad-mixtures in the lower elevations. Using what we call a «growth ecogram», we demonstrate species- and site-specific patterns of mean annual basal area increment and mean sensitivity of ring width (strength of year-to-year variation) for Fagus sylvatica, Quercus spp., Fraxinus excelsior, Picea abies, Abies alba and Pinus sylvestris, based on tree-ring data from 508 (co-)dominant trees on 27 locations. For beech, annual basal area increment ( average 1957–2006) was significantly correlated with tree height of the dominant sampling trees and proved itself as a possible alternative for assessing site quality. The fact that dominant trees of the different tree species showed partly similar growth potential within the same ecotype indicates comparable growth limitation by site conditions. Mean sensitivity of ring width – a measure of climate sensitivity – had decreased for oak and ash, while it had increased in pine. Beech showed diverging reactions with increasing sensitivity at productive sites (as measured by the C:N ratio of the topsoil), suggesting an increasing limitation by climate at these sites. Hence, we derive an important role of soil properties in the response of forests to climate change at lower elevations, which should be taken into account when estimating future forest productivity.


2021 ◽  
Vol 16 (3) ◽  
pp. 755-763
Author(s):  
M. Nagaraj M. Nagaraj ◽  
M. Udayakumar

A forest tree inventory study was conducted in Vallanadu Black buck sanctuary, Tuticorin. The current study was conducted to assess tree density, species richness, basal area (BA) and aboveground biomass (AGB) stockpile. The study area has been classified as Southern Thorn Forest (SFT). One hundred square plots (total area 1 ha), each 10m × 10m (100 m2 each) laid randomly across study area. All live trees with ≥5 cm diameter at breast height (DBH) measured at 137 cm above the ground. As the whole, 1335 individual trees ≥5cm DBH recorded. A total number of 18 species recorded from 14 genera and 11 families in study area. The family Mimosaceae has maximum number of species (7 species) followed by Rhamnaceae (2 species), while 9 families had just single species’ each. The total basal area recorded was 22.046 m2 ha-1, while, the mean wood density (WD) of trees estimated as 0.70±0.093 g cm-3. Total amount of 50.065 Mg ha-1 present in STF. The contribution of different species in terms of total AGB varied significantly. Commiphora berryi stocked 45.13% (22.588 Mg ha-1) of AGB followed by A. planifrons (23.31%, 11.669 Mg ha-1), A. mellifera (7.233%, 3.621 Mg ha-1), whereas remaining 15 species collectively stocked 24.327% (12.187 Mg ha-1) AGB. The STF had a large number of trees compared to some dry forests within Tamil Nadu. Southern Thorn Forest endowed with a moderate number of trees species. Aboveground biomass stockpile of trees is comparable with the range recorded from Indian dry forests. The study area experiences lesser mean annual rainfall and >6 months dry season. Further, endowed with short-bole and smaller leaved trees, hence stocked a relatively lesser AGB in trees.


2009 ◽  
Vol 85 (3) ◽  
pp. 387-391
Author(s):  
Mihai Pavel ◽  
Björn O Andersson

A model for predicting the value of forest stands was developed at FPInnovations – Feric Division. The model uses standard cruise data collected in British Columbia (BC) and company sort descriptions to predict the distribution of wood volume by species and grade sort for each proposed harvest site. The model is capable of quickly analyzing different scenarios (i.e., different sort sets) to reflect changing market conditions. Within the model, a taper equation is applied to each tree to calculate the diameters inside the bark, and quality and pathological descriptors from cruise data are used. A Dynamic Programming algorithm is used to predict the combination of logs that maximizes the value of each stem, and results are summarized and extended from individual trees to cruise plots, then to harvest blocks and/or stands. The model was successfully tested for second-growth stands with relatively few defects on Coastal BC. Improvements are being implemented to enhance its applicability to more complex stands. Key words: value of forest stands, economic operability, optimal bucking of trees, Dynamic Programming, computer model, inventory systems


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