Temporary Sample Plots Research Articles

Spatial and temporal heterogeneity of forest site productivity drivers: a case study within the eastern boreal forests of Canada

Forest productivity is driven by a suite of direct climatic and non-climatic factors that are transient or permanent. The kind of productivity driver and the nature of their effects vary by species, and scale dependencies potentially complicate these relationships. This study explored productivity-driver relations in eastern Boreal Canada and determined spatial effects in productivity control when expressed with stand dominant height at a reference age (site index). Data from 4,217 temporary sample plots obtained from boreal mixedwood and conifer bioclimatic domains, and with varied species composition, were used in this study. A single-level global model that assumes equal sensitivities across spatial scales was calibrated and compared with three alternative models reflecting different hypotheses on possible spatial heterogeneities. Alternative models were calibrated by plot-level soil deposit types (microscale), landscape dominant deposits (mesoscale) and bioclimatic domains (macroscale). A marked difference between the global and alternative models was observed, suggesting that a single global model does not sufficiently reflect existing heterogeneity in productivity-driver relationships. A combination of macro- and microscale models provided the best explanation of site index. Results further showed that site index is mainly driven by species composition (complementarity effects of aspen and jack pine compositions) and stand diameter structural diversity effects. It is concluded that successional changes, more than direct climatic effects, drive productivity.

Predicting stand volume using Quickbird and Landsat 7 ETM+ satellite images for stands of oriental beech (Fagus orientalis Lipsky): a case study inAyancık-Göldağ

Abstract: In forestry, inventory data is needed for ecological, economical and social values of forest and in preparing forest management planning. The planning process starts with forest inventory. In forestry, inventory data is obtained from both remotely sensed (aerial photo interpretation or satellite image) data and field survey with temporary sample plots. In the preparation of forest management plans, stand volume, basal area, number of trees stand as an important inventory data for the required parameters. Obtaining measurements of these parameters is costly and time consuming. This study were carried out to examine the Quickbird and Landsat 7 ETM+ satellite images in estimating stand volume in pure stands of oriental beech (Fagus orientalis Lipsky). The stand volume was determined by field measurements at total 70 temporary sampling plots. Reflectance values were calculated based on the Quickbird and Landsat 7 ETM+ satellite data points that correspond to the sampling plots. Regression analyses were conducted to examine the relationships between the reflectance values and stand volume. The results demonstrated that regression model with band 1, band 2, band 3 and band 4 as independent variables for Quickbird and ETM 2, ETM 3 and ETM 4 as independent variables for Landsat 7 ETM+ were used for a better estimation of stand volume (R2=0.70, RMSE=28.56 m3/ha-1; R2=0.545, RMSE=53.13 m3 ha-1), respectively. Keywords: Stand volume, Quickbird satellite data, Landsat 7 ETM+ satellite data

Tongue necrosis in a dog associated with the pine processionary caterpillar and its treatment

The patient was a 3-year-old English Setter that had been in contact with Thaumetopoea wilkinsoni larvae. Clinical examination revealed protrusion of the tongue outside of the mouth, edematous and swollen frenulum linguae and tongue, as well as a high amount of salivation. Necrotic and ulcerated areas were determined, particularly on the apex of the tongue. Treatment was carried out using systemic antihistamines, corticosteroids, antibiotics, vitamin C, and dexpanthenol, and the patient returned to good health.

Crown Ratio Models for Tectona grandis (Linn. f) Stands in Osho Forest Reserve, Oyo State, Nigeria

Crown ratio is the ratio of live crown length to tree height. It is often used as an important predictor variable for tree growth equation. It indicates tree vigor and is a useful parameter in forest health assessment. The objective of the study was to develop crown ratio prediction models for Tectona grandis. Based on the data set from the temporary sample plots, several non linear equations including logistics, Chapman Richard and exponential functions were tested. These functions were evaluated in terms of coefficient of determination () and standard error of the estimate (SEE). The significance of the estimated parameters was also verified. Plot of residuals against estimated crown ratios were observed. Although the logistic model had the highest and the least SEE, Chapman-Richard and Exponential functions were observed to be more consistent in their predictive ability; and were therefore recommended for predicting crown ratio in the stand.

A tool for converting forest ecosystem classifications for permanent or temporary growth plots into the new provincial Ecological Land Classification (ELC) system in the boreal regions of Ontario

Forest Ecosystem Classification (FEC) systems were originally developed and used in the Province of Ontario at regional levels with the objective of classifying forest ecosystems to support silvicultural decision-making in an operational setting. A new provincial Ecological Land Classification (ELC) system has been developed, which integrates the regional systems into a single consistent framework. To make continued use of data and knowledge gained from long-term forest monitoring plots classified under the old FEC system, such as Permanent Growth Plots (PGPs), Permanent Sample Plots (PSPs) and Temporary Sample Plots (TSPs), an ecosite conversion from the existing FEC data to the new ELC system was deemed necessary. We developed a conversion matrix to convert FEC ecosite classifications from the northeast and north-west to the provincial ELC system for the boreal forest region of Ontario. The conversion system is intended to apply at the scale of individual plots, with a special focus on PGP, PSP and TSP networks, and has been limited to forested ecosystems, as FEC systems were originally developed for the forest land base only. The conversion is primarily driven by canopy cover composition derived from plot-based individual tree data, with additional information required on substrate characteristics (e.g., substrate type, depth of mineral material, effective soil texture and moisture regime). It is possible to derive some of the soil variables from the broadly defined soil-type (S-type) categories of the original FEC systems; however, this approach requires making some assumptions that could reduce the accuracy of conversion. We anticipate that this conversion matrix will bridge the gap until active plot networks are re-typed in the field into the ELC system, provide a link to historical TSPs, and would be of general interest to a variety of new ELC users.

Avaliação Econômica dos Benefícios dos Macronutrientes em Diferentes Povoamentos de Bracatinga

A bracatinga e uma especie nativa, com papel importante na economia de pequenos proprietarios. Dessa forma, o presente trabalho foi desenvolvido com o intuito de quantificar o conteudo de macronutrientes presentes nos diferentes componentes da biomassa aerea de bracatingais nativos e, posteriormente, valorar economicamente os residuos florestais mantidos na area apos a exploracao. Os dados foram coletados em 304 parcelas temporarias, com diferentes idades, em povoamentos de bracatinga. Em ordem decrescente, os valores de macronutrientes encontrados na parte aerea dos bracatingais seguiram a sequencia: N > Ca > K > Mg > P. Apos a exploracao da lenha, restaram como remanescentes nas areas os residuos contendo uma media geral de 32% de Ca, 26% de Mg, 39% de N, 34% de P e 19% de K, com um equivalente monetario medio de fertilizantes (em reais.ha-1) variando de 303,56 a 1.140,78, dependendo do local e da classificacao de sitio da propriedade.

Black walnut (Juglans nigra L.) standing volume in the riparian forests of the Czech Republic

Black walnut (Juglans nigra L.) is one of the most valuable non-native tree species growing on alluvial soils in the southeastern part of the Czech Republic. However, its standing volume is currently calculated according to oak tables, although its growth and standing volume is likely different. In order to determine the observed black walnut standing volume and to express a difference between black walnut and other main tree species growing on alluvial soils, 63 temporary sample plots of pure black walnut stands were established and, for determination of tree volume, 63 sample trees with various dimensions were felled and measured in sections. Mensurational data were evaluated using a Korf growth function, which is one of best growth functions for expressing the development of standing volume. Moreover, a reciprocal Korf function was used for fitting the decline in the number of trees. For determination of standing volumes, 2 methods using Korf functions were used and their results were compared. The black walnut standing volume of 100 years is 706 m^3 ha^{-1} if we use the fitted mean diameter and height for calculation and 724 m^3 ha^{-1} if we use the Korf function for fitting the observed standing volumes in the sample plots. Both results are higher than the oak standing volume growing on the best site by 100 m^3 ha^{-1} and higher than the ash standing volume by approximately 200 m^3 ha^{-1}.

A silvicultural decision-support algorithm for density regulation within peatland black spruce stands

Determining the optimal density management regime for a given stand-level objective is a complex proposition faced by forest managers. Although decision-making for volumetric yield objectives has been greatly simplified with the advent of stand density management models, addressing new objectives arising from the paradigm shift towards the production of enhanced end-products and a broader array of ecosystem services remains a challenge when managing commercially-important boreal species. Consequently, the objectives of this study were to (1) develop an integrated modular-based structural stand density management model (SSDMM) and a corresponding algorithmic analogue for peatland black spruce ( Picea mariana (Mill.) BSP.) stands, and (2) given (1), demonstrate its utility as a crop planning tool within the context of silvicultural decision-making. The SSDMM was developed using 495 tree-list measurements obtained from 137 permanent and temporary sample plots, remeasurement data from 30 Nelder plots, and published relationships derived from diameter distribution and height–diameter modelling studies, density control experiments and sawmill simulation analyses. The resultant algorithm enabled the evaluation of the rotational consequences of competing density management regimes in terms of overall productivity, log-product distributions, biomass production and carbon yields, recoverable end-products and their associated monetary value, economic efficiency, duration of optimal site occupancy, structural stability, and wood fibre attributes. The utility of employing the model as a generic modelling platform for structural yield prediction for other species is also discussed.

A System of Growth Models for Even-Aged Pure Stands Based on the RICHARDS Growth Function (III) Estimation of the Parameters Using Data from Remeasured Temporary Sample Plots

A System of Growth Models for Even-Aged Pure Stands Based on the RICHARDS Growth Function (III) Estimation of the Parameters Using Data from Remeasured Temporary Sample Plots

A growth and yield model for even-aged Pinus brutia Ten. stands in Syria

Pinus brutia Ten. subspecies brutia, which occurs in the Eastern Mediterranean region, is the main forest species in Syria and important for multi-purpose forestry. In this study, 6,631 10-year past growth diameter increment measurements were taken in 83 temporary sample plots. The current breast height diameter of all trees was measured and a sample of trees was measured for height and age. The plots were placed so as to capture the whole range of variation in site quality, stand age and stand density. The data were used to develop the following models: The set of models enables the simulation of forest stand dynamics on an individual-tree basis.

From plots to landscape: A k-NN-based method for estimating stand-level merchantable volume in the Province of Québec, Canada

Estimation of forest attributes at the stand or polygon level across the forest domain is a basic component of forest inventory programs. We tested a “k-Nearest Neighbours” (k-NN)-based method for imputing merchantable volume. Our target dataset consisted of a discrete set of forest polygons within two large forest management units, and our reference dataset was a large historical database of temporary sample plots measured over the past three decades. The linkage between the target and reference datasets was provided by polygon-level photo-interpreted forest attributes. Measurements in temporary sample plots located in all target polygons enabled us to estimate fit statistics between imputed and measured merchantable volumes. A parallel imputation exercise was also done using the current operational method used by the Province of Québec to map forest attributes over the publicly owned forest lands. Results show that the volumes estimated using the historical k-NN method show fit statistics similar to those of the operational method, with a slightly higher bias that is largely within the error term of the estimates. For both methods, the coefficient of determination between measured and imputed merchantable volume is between 0.16 and 0.19 for total volume, increases substantially when the volume is partitioned between hardwoods and softwoods, but then decreases when the volume is further distributed among species. The results underline the importance of photo-interpretation uncertainties in bounding the accuracy of volume imputation as well as the value of the k-NN procedure for imputation purposes in the context of natural forests.Key words: Forest inventory; non-parametric methods; photo-interpretation; pre-stratification; natural forests

Plant communities and tree species associations in a Miombo ecosystem in the Lake Rukwa basin, Southern Tanzania: Implications for conservation

This study assessed the plant communities and species associations in the eastern Miombo woodlands eco-region of the Lake Rukwa basin southern Tanzania. Information was collected from 288 temporary sample plots in 32 sampling sites established randomly in the area and covering as much variation in the landscape as possible. Detailed analysis of the vegetation identified six tree communities of conservation importance, which included Brachystegia boehmii-Pericopsis angolensis woodland, Julbernardia globiflora woodland, Combretum molle-Sclerocarya birrea-Combretum zeyherii-Acacia seyal var fistula woodland, Bridelia cathartica-Diospyros mespiliformis woodland, Brachystegia busseiPterocarpus tinctorius woodland and Brachystegia microphylla-Isoberlinia tomentosa-Hymenocardia acida- Syzygium owariense woodland. Majority of the described plant communities are typical of Miombo ecosystems dominated by trees belonging mainly to the genera Brachystegia and Julbernardia. A mixture of non-legume species but typical of the Miombo ecosystem, however, dominates two out of six described plant communities. Apparently, there is high variability of plant communities in the Miombo ecosystem of southern Tanzania, an indication of the diverse nature of the Miombo ecosystem, also, an implication of high species diversity. This documentation on the patterns of species assemblages is the beginning of unveiling the diversity of assemblage of species in dry forest ecosystems which occupy a wide area in the region. These associations are important targets for conservation and monitoring vegetation changes in this ecosystem.

Usability of the Taurus Cedar and Crimean Pine in green belt afforestations in semiarid regions in Turkey: A case study in Konya Province Loros Mountain -Akyokus

n this study, root collar diameter and height development of 9 year-old saplings of Taurus Cedar (Cedrus libani) and Crimean Pine (Pinus nigra subsp. nigra var. caramanica) in the green belt afforestation areas were researched in Akyokus (130 ha) and Loros Mountain (140 ha) in Konya province. For this reason, root collar diameters and heights were measured at 4 temporary sample plots, each 450 m² (30 m × 15 m) containing randomized 5 experimental areas with 10 replicates. The data obtained from measurement were compared with ANOVA test. The root collar diameters of Crimean pines in Loros Mountain and heights of Taurus cedars in Akyokus were significantly different and higher. On the other hand, volumes of Crimean pines in Loros Mountain and Taurus cedar in Akyokus were significantly different in favor of these species. Thus, it might be suitable to use Crimean pine in Loros Mountain and Taurus cedar in Akyokus for green-belt afforestation studies in the future. Key words: Crimean Pine, green belt afforestation, height, root collar diameter, Taurus cedar.

Ecological and silvicultural indicatory value of plant-communities of Koto forest reserve (Centre-Benin)

A study was carried out in Koto forest reserve in central Benin (6°56’ to 7°02’ of north lat. and 02°03’ to 02°09’ of east long), in order to contribute to the sustainable management of the forest. Phytosociological inventory was done using the synusial approach. Soils were studied through texture surveys, pedological profiles description and laboratory analysis. Silvicultural parameters of plantations were studied using temporary sample plots of 300 m². The study helps to identify and describe twenty-two basic plantcommunities named synusia. Based on their relationships, the synusia have been combined to describe seven phytocoenoses (plant-communities). Each non pioneer phytocoenose is an expression of specific ecological conditions. The study of plantation productivity has shown remarkable homogeneity of productivity level within each non pioneer phytocoenose. Analysis of variance reveals a significant difference at 5% of probability level between the productivity levels of the phytocoenoses. Three productivity levels are identified according to phytocoenoses. The study leads to the conclusion that phytosociology is a reliable tool for forest management.

Growth and yield models for uneven-sized forest stands in Finland

Uneven-sized forestry is gradually gaining popularity and acceptability also in the Nordic countries. This is because of the willingness of the public and some forest owners to avoid clear-fellings and pursue more near-nature forest structures. It has also been realized that the profitability of uneven-sized forestry may be competitive with even-aged forestry. In Finland, management of uneven-sized stands is hampered by the lack of information about the dynamics of such stands, and about the yield and profitability of uneven-sized forestry. This study developed models which allow managers to simulate the growth and yield of uneven-sized stands in Finland, making it possible to predict the yield and analyze the sustainability of different management options. The model set consists of individual-tree diameter increment, height and survival models, and a model for ingrowth. The modeling data consisted of two long-term field experiments of uneven-sized forest management, a set of temporary sample plots measured earlier for growth modeling purposes, and the sample plots of the third National Forest Inventory of Finland. The application area of the models covers all growing sites, all main tree species, and the whole surface area of Finland. According to the models, the sustainable harvest of a fertile ( Oxalis-Myrtillus site) uneven-sized Norway spruce forest varies between 5.5 and 7 m 3 ha −1 a −1 in Central Finland, depending on the length of the cutting cycle, stand density, and shape of the diameter distribution. It is profitable to harvest large diameter classes more heavily than small ones. Due to the large amount of data the models for diameter increment are highly significant and reliably show the growth level of trees in uneven-sized stands. The weakest models are the ingrowth models, which are based on a clearly smaller data set than the other models.

Diameter at breast height-crown diameter prediction models for Picea orientalis

Seven models for predicting crown diameter using diameter at breast height were tested for Picea orientalis L. (Link.) in Artvin. Data were obtained from 4208 trees measured on 117 temporary sample plots. Sample plots were grouped into categories with 20 year mean age class intervals. Similarly, sample plots were grouped into categories based on mean tree diameter at breast height (2 cm diameter class interval). Mean diameter at breast height and mean crown diameter of sample plots in age class were analyzed statistically. One linear and six non-linear diameters at breast height-crown diameter functions were selected as candidate functions to model diameters at breast height -crown diameter relationship. Regression analysis showed that there were statistically significant (P > 0.05) and strong (R2 > 0.80) relationship between diameter at breast height and crown diameter variables in P. orientalis. The results of the study indicated that the diameter at breast height-crown diameter relationship can be described by cubic, compound, growth or exponential model because of the same R2 values. But the cubic model gave the best result for relationship between diameter at breast height and crown diameter. Key words: Crown diameter, diameter-crown diameter model, oriental spruce, regression analysis.

A simple growth and yield model for assessing changes in standing volume across Canada’s forests

We have adjusted two growth and yield models to temporary sample plots from across Canada, and used climate variables in lieu of phytometric indices such as site index to represent, in part, the site-level variability in growth potential. Comparison of predicted increments in plot-level height, basal area and merchantable wood volume to increments of these variables measured in permanent sample plots shows a moderate to poor predictive ability. Comparison with the performance of four operational growth and yield models from different provinces across Canada shows comparable predictive power of this new model versus that of the provincial models. Based on these results, we suggest that the simplification of regional growth and yield models may be achieved without further loss of predictive power, and that the large error in the prediction of growth increment is mostly associated with the use of temporary sample plots which, by definition, contain little information on stand dynamics. We also suggest that, because of the empirical nature of these growth and yield models, the scale of application should determine the appropriate scale of the model. National estimates of forest growth are therefore less likely to be biased if obtained from a national model only than if obtained from a combination of regional models, where those exist, gap-filled with estimates from a national model. Key words: yield model, merchantable wood volume, stand age, climatic variables, simultaneous regression, robust regression

Biomass equations for Scots pine and Norway spruce in Finland

In this study, biomass equations for the above- and below-ground tree components of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies [L.] Karst.) were developed. The models were based on 908 pine trees and 613 spruce trees collected in 77 stands located on mineral soil, and represented a wide range of stand and site conditions in Finland. The whole data set consisted of three sub data sets: 33 temporary sample plots, five thinning experiments, and the control plots of 39 fertilization experiments. The biomass equations were estimated for the individual tree components: stem wood, stem bark, living and dead branches, needles, stump, and roots. In the data analysis, a multivariate procedure was applied in order to take into account the statistical dependence among the equations. Three multivariate models for above-ground biomass and one for below-ground biomass were constructed. The multivariate model (1) was mainly based on tree diameter and height, and additional commonly measured tree variables were used in the multivariate models (2) and (3). Despite the unbalanced data in terms of the response variables, the statistical method generated equations that enable more flexible application of the equations, and ensure better biomass additivity compared to the independently estimated equations. The equations provided logical biomass predictions for a number of tree components, and were comparable with other functions used in Finland and Sweden even though the study material was not an objective, representative sample of the tree stands in Finland.

Validation of empirical yield curves for natural-origin stands in boreal Ontario

In Ontario, yield tables for forest management planning have remained relatively unchanged since initial work in the 1950s that was based on a limited number of temporary sample plots. In 2000, the Forestry Research Partnership accelerated work on the Benchmark Yield Curve Project (initiated several years earlier by the Ontario Ministry of Natural Resources, OMNR) to update these tables. The resulting yield curves incorporated data from more than 3000 permanent sample plots (PSPs) maintained in Ontario as well as PSPs from neighbouring and ecologically similar jurisdictions. Two stratifications were considered: OMNR’s Northeast Region standard forest units and leading species. The 10 forest units considered cover the major commercial species in the boreal forest in Ontario. Equations were fit to the data to predict the growth and yield by stratum. The equations were validated against independently collected data and compared to predictions from the current wood supply yield curves in Ontario: Plonski’s yield tables, modified Plonski, and northeast regional curves. Results of the validation showed that, with the exception of the MW2 and SF1 forest units, the new yield curves generally had less bias for gross total volume than Plonski and modified Plonski. Results for net merchantable volume were consistent with those for gross merchantable volume. The MW2 and SF1 forest units are more mixed in terms of species type, species light tolerance, and age. A leading species approach resulted in better predictions and is recommended for these forest units. Key words: wood supply, benchmark yield curves, mixedwood yield, yield model, Forestry Research Partnership

Assessment of the effect of quality factors on the assortment structure in poplar plantations

Quality factors affecting the assortment quality structure in poplar plantations were researched on nine temporary sample plots in the period 1997-2004, from the aspect of the implementation of roundwood standards. Sample plots were selected depending on the factors, the effect of which was studied. The following factors were researched: clonal species, planting pattern, flood risk, pruning of branches, plantation position and age. The study was performed by the original methodology. Based on the study results, it is concluded that knots have the highest effect on the assortment quality structure in poplar plantations, regardless of the site and stand conditions. Their effect rises significantly with the increase of tree diameter. Also, the analyses show that the number of large and rotten knots on the tree trunk increases considerably with the older age. In the flooded area, the sweep of the lower part of the stem is more intensive and multiple curvatures are frequent on the trees growing immediately along the river, whereas curvature decreases with the distance from the river bank. Based on the study results, it is concluded that the percentage of best quality assortments is considerably reduced by the above wood defects.