Tree crown ratio models for multi-species and multi-layered stands of southeastern British Columbia

2005 ◽  
Vol 81 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Hailemariam Temesgen ◽  
Valerie LeMay ◽  
Stephen J Mitchell
Keyword(s):  
British Columbia ◽  
Predictor Variable ◽  
Basal Area ◽  
Tree Height ◽  
Important Predictor ◽  
Tree Level ◽  
Crown Length ◽  
Growth Equations ◽  
Hardwood Tree ◽  
Variable Measurement

The ratio of live crown length to tree height (crown ratio; CR) is often used as an important predictor variable for tree level growth equations, particularly for multi-species and multi-layered stands. Also, CR indicates tree vigour and can be an important habitat variable. Measurement of CR for each tree can be time-consuming and difficult to obtain in very dense stands and for very tall trees where the base of live crown is obscured. Models to predict CR from size, competition and site variables were developed for several coniferous and one hardwood tree species growing in multispecies and multi-layered forest stands (complex stands) of southeastern British Columbia. Simple correlations indicated the expected relationships of CR decreasing with increasing height, and with increasing competition. A logistic model form was used to constrain predicted CR values to the interval [0,1]. Also, predictors were divided into tree size, stand competition, and site measures, and the contribution of each set of contributors was examined. For all models, height was an important predictor. The stand competition measure, basal area of larger trees, contributed significantly to predicting CR given that crown competition factor was also included as a measure of competition. Logical trends in CR versus size and competition variable groups were reflected by the models; site variable slightly improved predictions for some species. Much of the variability in CR was not accounted for, indicating that other variables are important for explaining CR changes in these complex stands. Key words: crown ratio, multi-species stands, multi-layered stands, basal area of larger trees

Estimation of foliage area in dense Montana lodgepole pine stands

1987 ◽  
Vol 17 (4) ◽  
pp. 320-324 ◽  
Author(s):  
Roger D. Hungerford
Keyword(s):  
Lodgepole Pine ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Area Ratio ◽  
Density Range ◽  
Sapwood Area ◽  
Crown Length ◽  
Pine Stands

Six stands of lodgepole pine, Pinuscontorta ssp. latifolia (Engelm.) Critchfield, in Montana were sampled to evaluate sapwood area (at 1.37 m and the crown base), basal area (at 1.37 m), tree height, and crown length as predictors of foliage area. Densities of the six stands ranged from 2900 to 17 800 stems/ha. This density range was picked to determine how stand density affects the ratio of foliage area to basal sapwood area. Regression estimates of foliage area using basal area and sapwood area at 1.37 m and the crown base were equally good. Within the sampled range of stand densities, differences in the foliage area to sapwood area ratio were not significant. The amount of foliage area served per unit of sapwood area (at 1.37 m) averaged 0.25 m2/cm2 for all 54 trees sampled. This value of foliage area per unit of sapwood area in dense stands was smaller than most other published values.

Factors affecting the relationship between sapwood area and leaf area of balsam fir

1992 ◽  
Vol 22 (11) ◽  
pp. 1684-1693 ◽  
Author(s):  
Marie R. Coyea ◽  
Hank A. Margolis
Keyword(s):  
Leaf Area ◽  
Basal Area ◽  
Tree Height ◽  
Balsam Fir ◽  
Tree Age ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Crown Length ◽  
Basal Area Growth ◽  
Area Growth

The ratio between projected leaf area (LA) and cross-sectional sapwood area (SA) of dominant and codominant balsam fir trees (Abiesbalsamea (L.) Mill.) was determined in 24 forest stands across the province of Quebec. Various physical factors proposed in the Whitehead hydraulic model, and some of the easily measured surrogates of these factors, were tested for their influence on LA:SA ratios. Average growing season vapor pressure deficit, temperature, precipitation, and stand drainage class did not significantly influence LA:SA ratios. On the other hand, LA:SA ratios were positively influenced by sapwood permeability (k), tree height, and crown length. As suggested by the model, there was a positive correlation between sapwood permeability and LA:SA ratio and a negative correlation between tree height or crown length and LA/(SA k). Increases in sapwood permeability with tree age were associated with longer tracheids having larger lumen diameters. Of the various empirical factors tested, only site quality, 5-year basal area growth, and age had a significant influence on LA:SA ratios. Sapwood cross-sectional area at breast height by itself was a reasonable linear predictor of LA for all stands (LA = −0.158 + 0.709 SABH, R2 = 0.75). Using the variables that were previously determined to influence LA:SA ratios, stepwise regressions revealed that only crown length and 5-year basal area growth significantly improved linear predictions of LA based on sapwood area. However, the increase in R2 was relatively modest, i.e., 0.83 for all three independent variables versus 0.75 for SA alone. The results from this study will be useful in integrating physiologically based measurements, such as growth efficiency, into standard forest inventory practices for balsam fir and thus could be beneficial in developing new silvicultural strategies for protecting Quebec's forest resource.

Crown rise due to competition drives biomass allocation in silver birch

2003 ◽  
Vol 33 (12) ◽  
pp. 2395-2404 ◽  
Author(s):  
Sakari Ilomäki ◽  
Eero Nikinmaa ◽  
Annikki Mäkelä
Keyword(s):  
Basal Area ◽  
Tree Height ◽  
Silver Birch ◽  
Cross Sectional ◽  
Functional Balance ◽  
Crown Length ◽  
Pipe Model ◽  
Strong Linear Correlation ◽  
Total Cross Sectional Area ◽  
Study Support

This study tests the hypothesis that the aboveground structure of silver birch (Betula pendula L.) is derivable from crown rise across a range of social positions of trees. Data were measured in 30-year-old birch monocultures of three different initial spacings. As suggested by the pipe model, there was a strong linear correlation between the total cross-sectional area of branches and that of stem at crown base. Foliage mass correlated with stem basal area at crown base. An allometric relationship was found between foliage mass and crown length, and the mean length (weighted by basal area) of branches correlated linearly with crown length. Pipe ratios of branches and foliage were found to be independent of slenderness (= tree height / breast height diameter). The proportion of stem in aboveground biomass increased from 80% to 96% when the slenderness index increased, the proportions of branches and leaves decreasing, respectively. For crown biomass, the proportion of foliage was greater in the more slender stems, accompanied with a corresponding decrease in the proportion of stems, while the share of branches remained rather constant. The ratio of productive (foliage) and nonproductive (stem plus branches) biomass inside the crown was positively correlated with slenderness, but in the whole tree, the ratio declined with increasing slenderness. The results of this study support the theory of functional balance and seem to be in conflict with the priority principle of allocation.

scholarly journals Relascope sampling for crown ratio estimation

2013 ◽  
Vol 43 (5) ◽  
pp. 459-468 ◽  
Author(s):  
Sebastian Schnell ◽  
Jonas Wikman ◽  
Göran Ståhl
Keyword(s):  
Measurement Errors ◽  
Basal Area ◽  
Tree Height ◽  
Sampling Errors ◽  
Forest Stands ◽  
Vertical Angle ◽  
Pilot Studies ◽  
Crown Length ◽  
Study Sites ◽  
Angle Count Sampling

In this study, we apply vertical angle count sampling to estimate the crown ratio of trees in unthinned forest stands. The rationale is to be able to quickly assess the relative crown size of forest stands to support thinning decisions by simply counting trees. We provide estimators and discuss their precision based on pilot studies in Scots pine (Pinus sylvestris L.) plantations in northern Sweden. A separate study was conducted to investigate the amount of measurement errors, i.e., how many trees are wrongly selected or overlooked when using the method. Sampling errors for estimating crown ratio were found to be remarkably low, partly due to high correlation between crown length and tree height and partly due to low variability in the study sites. Measurement errors were in the range of what is commonly obtained with horizontal angle count sampling for basal area estimation.

scholarly journals Slenderness of pedunculate oak (Quercus robur L.) according to biosocial position

2018 ◽  
Vol 73 (3) ◽  
pp. 37-43
Author(s):  
ZDZISŁAW KACZMARSKI ◽  
KATARZYNA MASTERNAK ◽  
MATEUSZ JARMUŁ
Keyword(s):  
Basal Area ◽  
Tree Height ◽  
Projection Area ◽  
Pedunculate Oak ◽  
Single Tree ◽  
Crown Length ◽  
Crown Width ◽  
Growth Space ◽  
Oak Tree ◽  
Crown Projection Area

The paper presents results of an analysis of pedunculate oak slenderness. The dependence between slenderness of the oak tree and dimensions of the trunk and the crown dimensions of a single tree were examined. The biosocial position of each tree was determined based on the Kraft’s classification criteria. Following dimensions were measured for each tree: height, height of base of live crown, crown radius, diameter at breast height. The following crown parameters related to the growth space of a single tree were determined: crown length, crown width, crown projection area, space of a single tree, Seebach’s growth space number, crown projection area to basal area ratio, crown spread. Based on the obtained results, the following was found: biosocial position of the oak tree in vertical structure of the stand has significant impact on the size of the tree slenderness; the slenderness increases with deterioration of the biosocial position of the tree, but it decreases with the increase in the value of the tree’s measurement characteristics and the measures of its crown. 

scholarly journals Projecting the Growth of Loblolly Pine in a Changing Atmosphere

1999 ◽  
Vol 23 (4) ◽  
pp. 212-216 ◽  
Author(s):  
Harry T. Valentine ◽  
Ralph L. Amateis ◽  
Harold E. Burkhart ◽  
Timothy G. Gregoire ◽  
David Y. Hollinger ◽  
...  
Keyword(s):  
Loblolly Pine ◽  
Dry Matter ◽  
Carbon Allocation ◽  
Average Rate ◽  
Carbon Dioxide Concentration ◽  
Basal Area ◽  
Tree Height ◽  
Atmospheric Concentration ◽  
Crown Length ◽  
Rate Of Increase

Abstract Recent findings regarding the magnitude of the influence of carbon dioxide concentration on the rate of photosynthesis in loblolly pine have been incorporated into Pipestem, a model of carbon allocation and growth. Pipestem translates photosynthetic rates into rates of change in stand basal area, quadratic mean diameter, tree density, average tree height, average crown length, dominant tree height, and woody dry matter. Projections of loblolly pine growth were run under the assumption that the atmospheric concentration of CO2 will continue to increase by 1.6 ppm/yr, the average rate of increase in the last 10 yr. Standing crops of woody dry matter in 20-yr-old loblolly pine stands in Buckingham County, Virginia, are projected to increase, on the average, by 9.8% in 20 yr. It is concluded that the CO2 effect should be accounted for in long-term projections of loblolly pine growth. South. J. Appl. For. 23(4):212-216.

scholarly journals The applicability of the Pipe Model Theory in trees of Scots pine of Poland

2008 ◽  
Vol 54 (No. 11) ◽  
pp. 519-531 ◽  
Author(s):  
T. Jelonek ◽  
W. Pazdrowski ◽  
M. Arasimowicz ◽  
A. Tomczak ◽  
R. Walkowiak ◽  
...  
Keyword(s):  
Model Theory ◽  
Basal Area ◽  
Tree Height ◽  
Sapwood Area ◽  
Main Layer ◽  
Crown Length ◽  
Pipe Model ◽  
Natural Range ◽  
Pipe Model Theory ◽  
Area And Volume

In order to test the application importance of the <I>Pipe Model Theory</I> and to develop models for the share of sapwood in tree stems, a total of 114 Scots pines (<I>Pinus sylvestris</I> L.) were felled within the natural range of this species in three natural positions located in northern and western Poland. The analyses were conducted on wood coming from trees from the main layer of the stand, i.e. the first three classes according to the classification developed by Kraft. Dependences were analyzed between the biometric characteristics of model trees, e.g. tree height, diameter at breast height, crown length, crown basal area and the area and volume of sapwood in the stem. All the analyzed characteristics, both biometric traits and sapwood characteristics, were found to be correlated significantly (<I>P</I> < 0.05) positively. Conducted analyses indicate that the postulates proposed in the <I>Pipe Model Theory</I> and <I>Profile Theory</I> require certain modifications and regression models developed for each social class of tree position in the stand for dependences of sapwood area and volume on the above mentioned biometric variables indirectly include changes occurring in time.

Predicting maximum branch diameter from crown dimensions, stand characteristics and tree species

2011 ◽  
Vol 87 (04) ◽  
pp. 542-551 ◽  
Author(s):  
Arthur Groot ◽  
Robert Schneider
Keyword(s):  
Tree Species ◽  
Wood Quality ◽  
Basal Area ◽  
Tree Height ◽  
Remotely Sensed Data ◽  
Individual Tree ◽  
Branch Diameter ◽  
Crown Length ◽  
Stand Basal Area ◽  
Stand Characteristics

Forest resource inventories must include wood quality information to support the optimum use of wood fibre. The objective of this study was to develop models relating maximum live branch diameter (MBD), which affects lumber value, to tree and stand characteristics that can be measured through current and emerging remote sensing technologies. Using non-linear mixed effects models for six Canadian conifer species, as well as for three broad-leaved species, MBD was related to crown radius, tree height, crown length, stand basal area, and basal area of trees larger than the subject tree. Models that included only individual tree characteristics (crown radius, tree height, and crown length) did not perform as well as models that additionally included stand characteristics (stand basal area and basal area of larger trees). Models that took into account tree species performed better than models that did not; in particular, broadleaved species had much thicker branches than conifers. The best model did not show bias with respect to independent variables and had root mean square error of 0.32 cm. For the best model, prediction error was not related to silvicultural treatment. These model characteristics strongly support the potential to successfully predict MBD from remotely sensed data.

Effects of neighbours on crown length of Abies lasiocarpa and Picea engelmannii in two old-growth stands in British Columbia

2010 ◽  
Vol 40 (4) ◽  
pp. 638-647 ◽  
Author(s):  
Joseph A. Antos ◽  
Roberta Parish ◽  
Gordon D. Nigh
Keyword(s):  
British Columbia ◽  
Vertical Structure ◽  
Tree Height ◽  
Picea Engelmannii ◽  
Abies Lasiocarpa ◽  
Crown Architecture ◽  
Mixed Species ◽  
Old Growth ◽  
Crown Length

Crown length is a key aspect of vertical structure in multi-aged, multistrata, mixed-species forests. Crown length, defined as the distance from the tree top to the lowest live branch whorl, was determined for 3169 mapped trees ≥4.0 cm in diameter, in four 0.25 ha plots in each of two old-growth Abies lasiocarpa  (Hook.) Nutt. – Picea engelmannii Parry ex Engelm. stands. We randomly selected half the trees to build models and half for validation. Crown length was modelled as a function of tree height, incorporating modifiers to account for neighbouring trees. The inclusion radius and height threshold for competition were 3 m and 70%, respectively. The addition of two modifiers significantly improved the model for A. lasiocarpa; crown length decreased as the number of neighbours increased and as the height of surrounding trees increased. In contrast, none of the modifiers significantly improved the model for P. engelmannii. Except at high levels of competition, Abies crowns were longer than those of Picea. However, both species in these forests have long crowns, typically three-quarters of the tree height and rarely less than half. The tightly programmed conical crown architecture of these species likely contributes to long crowns and to the limited effects of neighbours on crown length.

scholarly journals A protocol for sampling vascular epiphyte richness and abundance

2009 ◽  
Vol 25 (2) ◽  
pp. 107-121 ◽  
Author(s):  
Jan H. D. Wolf ◽  
S. Robbert Gradstein ◽  
Nalini M. Nadkarni
Keyword(s):  
Tree Height ◽  
Dry Weight ◽  
Mantel Test ◽  
Tree Size ◽  
Tree Level ◽  
Trunk Diameter ◽  
Host Trees ◽  
Epiphyte Communities ◽  
Vascular Epiphyte

Abstract:The sampling of epiphytes is fraught with methodological difficulties. We present a protocol to sample and analyse vascular epiphyte richness and abundance in forests of different structure (SVERA). Epiphyte abundance is estimated as biomass by recording the number of plant components in a range of size cohorts. Epiphyte species biomass is estimated on 35 sample-trees, evenly distributed over six trunk diameter-size cohorts (10 trees with dbh > 30 cm). Tree height, dbh and number of forks (diameter > 5 cm) yield a dimensionless estimate of the size of the tree. Epiphyte dry weight and species richness between forests is compared with ANCOVA that controls for tree size. SChao1 is used as an estimate of the total number of species at the sites. The relative dependence of the distribution of the epiphyte communities on environmental and spatial variables may be assessed using multivariate analysis and Mantel test. In a case study, we compared epiphyte vegetation of six Mexican oak forests and one Colombian oak forest at similar elevation. We found a strongly significant positive correlation between tree size and epiphyte richness or biomass at all sites. In forests with a higher diversity of host trees, more trees must be sampled. Epiphyte biomass at the Colombian site was lower than in any of the Mexican sites; without correction for tree size no significant differences in terms of epiphyte biomass could be detected. The occurrence of spatial dependence, at both the landscape level and at the tree level, shows that the inclusion of spatial descriptors in SVERA is justified.

Sign in / Sign up

Export Citation Format

Share Document