Evaluating the shelterwood harvesting system after 25 years in a beech Fagus orientalis Lipsky) forest in Iran

Beech (Fagus orientalis Lipsky) is the most industrial commercial tree species among more than 80 broadleaved trees and shrubs in Hyrcanian forests. In this study some of the silvicultural properties of beech were studied under a shelterwood cutting system in a regeneration unit of 25 years old stand in Sangdeh forests of Iran. Tree height, diameter, canopy cover, variety of species, frequency at different stages of growth (seedling, sapling, thicket and pole) and tree density at juvenile phase were recorded in 431 circular 1,000 m2 sample plots before and after shelterwood cutting. Results indicated that tree density in the diameter at breast height (dbh) class of < 20 cm increased during shelterwood cutting. Canopy cover of regeneration unit was 78.5% in 1957, while in 2000 and after the shelterwood cutting it reached 59%. Growing stages of regeneration were 14% sapling, 21% thicket, 24% small pole and 41% pole. The shelterwood method has not been very successful in our study area due to a number of technical and potential problems.

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Estimation of Genetic Parameters and Wood Yield Selection Index in a Clonal Trial of Korean Pine (Pinus koraiensis) in Northeastern China

Sustainability ◽

10.3390/su13084167 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4167

Author(s):

David Kombi Kaviriri ◽

Huan-Zhen Liu ◽

Xi-Yang Zhao

Keyword(s):

Selection Index ◽

Tree Height ◽

Stem Volume ◽

Korean Pine ◽

Branch Number ◽

Basal Diameter ◽

Diameter At Breast Height ◽

Breast Height ◽

Stem Straightness ◽

Clonal Trial

In order to determine suitable traits for selecting high-wood-yield Korean pine materials, eleven morphological characteristics (tree height, basal diameter, diameter at breast height, diameter at 3 meter height, stem straightness degree, crown breadth, crown height, branch angle, branch number per node, bark thickness, and stem volume) were investigated in a 38-year-old Korean pine clonal trial at Naozhi orchard. A statistical approach combining variance and regression analysis was used to extract appropriate traits for selecting elite clones. Results of variance analysis showed significant difference in variance sources in most of the traits, except for the stem straightness degree, which had a p-value of 0.94. Moderate to high coefficients of variation and clonal repeatability ranged from 10.73% to 35.45% and from 0.06% to 0.78%, respectively. Strong significant correlations on the phenotypic and genotypic levels were observed between the straightness traits and tree volume, but crown breadth was weakly correlated to the volume. Four principal components retaining up to 80% of the total variation were extracted, and stem volume, basal diameter, diameter at breast height, diameter at 3 meter height, tree height, and crown height displayed high correlation to these components (r ranged from 0.76 to 0.98). Based on the Type III sum of squares, tree height, diameter at breast height, and branch number showed significant information to explain the clonal variability based on stem volume. Using the extracted characteristics as the selection index, six clones (PK105, PK59, PK104, PK36, PK28, and K101) displayed the highest Qi values, with a selection rate of 5% corresponding to the genetic gain of 42.96% in stem volume. This study provides beneficial information for the selection of multiple traits for genetically improved genotypes of Korean pine.

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Development and Performance Evaluation of a Very Low-Cost UAV-Lidar System for Forestry Applications

Remote Sensing ◽

10.3390/rs13010077 ◽

2020 ◽

Vol 13 (1) ◽

pp. 77

Author(s):

Tianyu Hu ◽

Xiliang Sun ◽

Yanjun Su ◽

Hongcan Guan ◽

Qianhui Sun ◽

...

Keyword(s):

Forest Inventory ◽

Low Cost ◽

Canopy Cover ◽

Tree Height ◽

Flying Height ◽

Tree Level ◽

Forest Site ◽

Lidar System ◽

Individual Tree ◽

Gap Fraction

Accurate and repeated forest inventory data are critical to understand forest ecosystem processes and manage forest resources. In recent years, unmanned aerial vehicle (UAV)-borne light detection and ranging (lidar) systems have demonstrated effectiveness at deriving forest inventory attributes. However, their high cost has largely prevented them from being used in large-scale forest applications. Here, we developed a very low-cost UAV lidar system that integrates a recently emerged DJI Livox MID40 laser scanner (~$600 USD) and evaluated its capability in estimating both individual tree-level (i.e., tree height) and plot-level forest inventory attributes (i.e., canopy cover, gap fraction, and leaf area index (LAI)). Moreover, a comprehensive comparison was conducted between the developed DJI Livox system and four other UAV lidar systems equipped with high-end laser scanners (i.e., RIEGL VUX-1 UAV, RIEGL miniVUX-1 UAV, HESAI Pandar40, and Velodyne Puck LITE). Using these instruments, we surveyed a coniferous forest site and a broadleaved forest site, with tree densities ranging from 500 trees/ha to 3000 trees/ha, with 52 UAV flights at different flying height and speed combinations. The developed DJI Livox MID40 system effectively captured the upper canopy structure and terrain surface information at both forest sites. The estimated individual tree height was highly correlated with field measurements (coniferous site: R2 = 0.96, root mean squared error/RMSE = 0.59 m; broadleaved site: R2 = 0.70, RMSE = 1.63 m). The plot-level estimates of canopy cover, gap fraction, and LAI corresponded well with those derived from the high-end RIEGL VUX-1 UAV system but tended to have systematic biases in areas with medium to high canopy densities. Overall, the DJI Livox MID40 system performed comparably to the RIEGL miniVUX-1 UAV, HESAI Pandar40, and Velodyne Puck LITE systems in the coniferous site and to the Velodyne Puck LITE system in the broadleaved forest. Despite its apparent weaknesses of limited sensitivity to low-intensity returns and narrow field of view, we believe that the very low-cost system developed by this study can largely broaden the potential use of UAV lidar in forest inventory applications. This study also provides guidance for the selection of the appropriate UAV lidar system and flight specifications for forest research and management.

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Adjudicating Perspectives on Forest Structure: How Do Airborne, Terrestrial, and Mobile Lidar-Derived Estimates Compare?

Remote Sensing ◽

10.3390/rs13122297 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2297

Author(s):

Jonathon J. Donager ◽

Andrew J. Sánchez Meador ◽

Ryan C. Blackburn

Keyword(s):

Ponderosa Pine ◽

Laser Scanning ◽

Canopy Cover ◽

Basal Area ◽

Tree Height ◽

Absolute Error ◽

Forest Monitoring ◽

Individual Tree ◽

Structural Configurations ◽

Individual Trees

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.

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Seemingly Unrelated Mixed-Effects Biomass Models for Black Locust in West Poland

Forests ◽

10.3390/f12030380 ◽

2021 ◽

Vol 12 (3) ◽

pp. 380

Author(s):

Karol Bronisz ◽

Szymon Bijak ◽

Rafał Wojtan ◽

Robert Tomusiak ◽

Agnieszka Bronisz ◽

...

Keyword(s):

Black Locust ◽

Random Effect ◽

Tree Height ◽

Cross Model ◽

Diameter At Breast Height ◽

Breast Height ◽

Dependent Variables ◽

Dry Biomass ◽

Biomass Components ◽

Independent Variable

Information about tree biomass is important not only in the assessment of wood resources but also in the process of preparing forest management plans, as well as for estimating carbon stocks and their flow in forest ecosystems. The study aimed to develop empirical models for determining the dry mass of the aboveground parts of black locust trees and their components (stem, branches, and leaves). The research was carried out based on data collected in 13 stands (a total of 38 sample trees) of black locust located in western Poland. The model system was developed based on multivariate mixed-effect models using two approaches. In the first approach, biomass components and tree height were defined as dependent variables, while diameter at breast height was used as an independent variable. In the second approach, biomass components and diameter at breast height were dependent variables and tree height was defined as the independent variable. Both approaches enable the fixed-effect and cross-model random-effect prediction of aboveground dry biomass components of black locust. Cross-model random-effect prediction was obtained using additional measurements of two extreme trees, defined as trees characterized by the smallest and largest diameter at breast height in sample plot. This type of prediction is more precise (root mean square error for stem dry biomass for both approaches equals 77.603 and 188.139, respectively) than that of fixed-effects prediction (root mean square error for stem dry biomass for both approaches equals 238.716 and 206.933, respectively). The use of height as an independent variable increases the possibility of the practical application of the proposed solutions using remote data sources.

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Augmentation of Traditional Forest Inventory and Airborne Laser Scanning with Unmanned Aerial Systems and Photogrammetry for Forest Monitoring

Remote Sensing ◽

10.3390/rs10101562 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1562 ◽

Cited By ~ 17

Author(s):

Kathryn Fankhauser ◽

Nikolay Strigul ◽

Demetrios Gatziolis

Keyword(s):

Laser Scanning ◽

Canopy Cover ◽

Tree Height ◽

Forest Monitoring ◽

Unmanned Aerial Systems ◽

Aerial Laser Scanning ◽

Forest Inventories ◽

Airborne Laser ◽

Aerial Systems

Forest inventories are constrained by resource-intensive fieldwork, while unmanned aerial systems (UASs) offer rapid, reliable, and replicable data collection and processing. This research leverages advancements in photogrammetry and market sensors and platforms to incorporate a UAS-based approach into existing forestry monitoring schemes. Digital imagery from a UAS was collected, photogrammetrically processed, and compared to in situ and aerial laser scanning (ALS)-derived plot tree counts and heights on a subsample of national forest plots in Oregon. UAS- and ALS-estimated tree counts agreed with each other (r2 = 0.96) and with field data (ALS r2 = 0.93, UAS r2 = 0.84). UAS photogrammetry also reasonably approximated mean plot tree height achieved by the field inventory (r2 = 0.82, RMSE = 2.92 m) and by ALS (r2 = 0.97, RMSE = 1.04 m). The use of both nadir-oriented and oblique UAS imagery as well as the availability of ALS-derived terrain descriptions likely sustain a robust performance of our approach across classes of canopy cover and tree height. It is possible to draw similar conclusions from any of the methods, suggesting that the efficient and responsive UAS method can enhance field measurement and ALS in longitudinal inventories. Additionally, advancing UAS technology and photogrammetry allows diverse users access to forest data and integrates updated methodologies with traditional forest monitoring.

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Field Evaluation of Populus deltoides Bartr. ex Marsh. at Two Sites in Indo-gangetic Plains of India

Silvae Genetica ◽

10.1515/sg-2010-0001 ◽

2010 ◽

Vol 59 (1-6) ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

G. P. S. Dhillon ◽

Avtar Singh ◽

Pritpal Singh ◽

D. S. Sidhu

Keyword(s):

Populus Deltoides ◽

Growth Traits ◽

Tree Height ◽

Field Evaluation ◽

Site Conditions ◽

Genetic Advance ◽

Gangetic Plains ◽

Diameter At Breast Height ◽

Breast Height ◽

Northwestern India

Abstract Results from clonal trials of Populus deltoides conducted in two distinct agroclimatic regions of Punjab in northwestern India are reported and discussed. Sixteen clones were evaluated at Hambran and Bathinda where commonly grown clone ‘G-48’ was considered as control. Significant differences among clones (P < 0.001) were observed for diameter at breast height (DBH), tree height and volume at the age of four and six years under both the site conditions. Clone ‘L-48’ ranked first for volume at six year age at both sites and was followed by clone ‘Ranikhet’. The respective superiority for volume of these clones over control was 44.8 and 23.2 per cent at Hambran and 72.5 and 30.7 per cent at Bathinda. All growth traits registered significantly higher values at Hambran in comparison to those at Bathinda. Clone x site interaction was also significant (P < 0.001). The clones ‘L-168’, ‘154/86’, ‘Solan-z’ and ‘170/88’ experienced huge fluctuation in ranking between sites for volume at 6-year age. The DBH and height showed significant and positive correlation with each other and with tree volume at all the age combinations. The clonal mean heritability was quite high both at Hambran (0.73-0.86) and Bathinda (0.80-0.95). The genetic advance were the highest for volume (33.34-64.26%) and the lowest (10.65-22.79%) in case of height.

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Contribution of some Acacia Species on Carbon Sequestration in Blue Nile State, Sudan

10.51527/v2i1.13me ◽

2021 ◽

pp. 97-105

Keyword(s):

Carbon Sequestration ◽

Wood Density ◽

Carbon Stock ◽

Tree Height ◽

Biomass Estimation ◽

Expansion Factor ◽

Wood Volume ◽

Crown Diameter ◽

Breast Height ◽

Acacia Seyal

Background: The current challenge is to reduce the uncertainties in obtaining accurate and reliable data of carbon stock changes and emission factors essential for reporting national inventories. Improvements in above ground biomass estimation can also help account for changes in carbon stock in forest areas that may potentially participate in the Reducing emissions from deforestation and forest degradation and other initiatives. Current objectives for such estimates need a unified approach which can be measurable, reportable, and verifiable. This might result to a geographically referenced biomass density database for Sudanese forests that would reduce uncertainties in estimating forest aboveground biomass. The main objective: of this study is to assess potential of some selected forest variables for modeling carbon sequestration for Acacia seyal, vr. Seyal, Acacia seyal, vr. fistula, Acacia Senegal. The specific objectives include development of empirical allometric models for forest biomass estimation, estimation of carbon sequestration for these tree species, estimation of carbon sequestration per hectare and comparing the amount with that reported to the region. A total of 10 sample trees for biomass and carbon determination were selected for each of the three species from El Nour Natural Forest Reserve of the Blue Nile State, Sudan. Data of diameter at breast height, total tree height, tree crown diameter, crown height, and upper stem diameters were measured. Then sample trees were felled and sectioned to their components, and weighed. Subsamples were selected from each component for oven drying at 105 ˚C. Finally allometric models were developed and the aboveground dry weight (dwt) and carbon sequestered per hector were calculated. The results: presents biomass equations, biomass expansion factor and wood density that developed for the trees. In case of inventoried wood volume, corrections for biomass expansion factor and wood density value were done, and new values are suggested for use to convert wood volume to biomass estimates. The results also, indicate that diameter at breast height, crown diameter and tree height are good predictors for estimation of tree dwt and carbon stock. Conclusion: The developed allometric equations in this study gave better estimation of dwt than default value. The average carbon stock was found to be 22.57 t/ha.

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Evaluation of the Relative Stem Taper Curves Estimated Only from Tree Height and Diameter at Breast Height:

Journal of the Japanese Forest Society ◽

10.4005/jjfs.94.188 ◽

2012 ◽

Vol 94 (4) ◽

pp. 188-191 ◽

Cited By ~ 1

Author(s):

Megumi Ishida ◽

Satoshi Naoi ◽

Yasumasa Watanabe ◽

Akinori Tsuzuku ◽

Masaya Aoki

Keyword(s):

Tree Height ◽

Diameter At Breast Height ◽

Breast Height ◽

Stem Taper

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Tree crown size as a measure of tree biosocial position in 135-year-old oak (Quercus L.) stand

Folia Forestalia Polonica ◽

10.1515/ffp-2016-0004 ◽

2016 ◽

Vol 58 (1) ◽

pp. 31-42 ◽

Cited By ~ 1

Author(s):

Katarzyna Kaźmierczak ◽

Bogna Zawieja

Keyword(s):

Principal Component ◽

Tree Height ◽

Projection Area ◽

Tree Crown ◽

Diameter At Breast Height ◽

Breast Height ◽

Crown Length ◽

Pca Method ◽

Crown Projection Area

AbstractThe paper presents an attempt to apply measurable traits of a tree – crown projection area, crown length, diameter at breast height and tree height for classification of 135-year-old oak (QuercusL.) trees into Kraft classes. Statistical multivariate analysis was applied to reach the aim. Empirical material was collected on sample plot area of 0.75 ha, located in 135-year-old oak stand. Analysis of dimensional traits of oaks from 135-year-old stand allows quite certain classification of trees into three groups: pre-dominant, dominant and co-dominant and dominated ones. This seems to be quite promising, providing a tool for the approximation of the biosocial position of tree with no need for assessment in forest. Applied analyses do not allow distinguishing trees belonging to II and III Kraft classes. Unless the eye-estimation-based classification is completed, principal component analysis (PCA) method provided simple, provisional solution for grouping trees from 135-year-old stand into three over-mentioned groups. Discriminant analysis gives more precise results compared with PCA. In the analysed stand, the most important traits for the evaluation of biosocial position were diameter at breast height, crown projection area and height.

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Degradation or recovery of argan woodlands in South Morocco? Tree count from satellite imagery between 1967–2019 may underestimate pressures on dryland forests status

10.5194/egusphere-egu21-2612 ◽

2021 ◽

Author(s):

Irene Marzolff ◽

Mario Kirchhoff ◽

Robin Stephan ◽

Manuel Seeger ◽

Ali Aït Hssaïne ◽

...

Keyword(s):

Forest Cover ◽

Canopy Cover ◽

Biosphere Reserve ◽

Agroforestry System ◽

Tree Density ◽

Tree Cover ◽

Positive Development ◽

Natural State ◽

Remotely Sensed Data ◽

Change Analysis

In semi-arid to arid South-west Morocco, the once ubiquitous endemic argan tree (Argania spinosa) forms the basis of a traditional silvo-pastoral agroforestry system with complex usage rights involving pasturing and tree-browsing by goats, sheep and camels, smallholder agriculture and oil production. Widespread clearing of the open-canopy argan forests has been undertaken in the 12th&#8211;17th century for sugarcane production, and again in the 20th century for fuelwood extraction and conversion to commercial agriculture. The remaining argan woodlands have continued to decline due to firewood extraction, charcoal-making, overgrazing and overbrowsing. Soil and vegetation are increasingly being degraded; natural rejuvenation is hindered, and soil-erosion rates rise due to reduced infiltration and increased runoff. Numerous studies indicate that tree density and canopy cover have been generally decreasing for the last 200 years. However, there is little quantitative and spatially explicit information about these forest-cover dynamics.In our study, the tree-cover change between 1967 and 2019 was analysed for 30 test sites of 1 ha each in argan woodlands of different degradation stages in the provinces of Taroudant, Agadir Ida-Outanane and Chtouka-A&#239;t Baha. We used historical black-and-white satellite photography from the American reconnaissance programme CORONA, recent high-resolution multispectral imagery from the commercial WorldView satellites and ultrahigh resolution small-format aerial photography taken with an unmanned aerial system (UAS) to map the presence, absence and comparative crown-size class of 2610 trees in 1967 and 2019. We supplemented the remotely-sensed data with field observations on tree structure and architecture.Results show that plant densities reach up to 300 argan trees and shrubs per hectare, and the mean tree density has increased from 58 trees/ha in 1967 to 86 trees/ha in 2019. While 7% of the 1967 trees have vanished today, more than one third of today&#8217;s trees could not be observed in 1967. This positive change has a high uncertainty, however, as most of the increase concerns small trees (< 3 m diameter) which might have been missed on the lower-resolution CORONA images.When combined with our field data on tree architecture, tree count &#8211; albeit a parameter easily attained by remote sensing &#8211; is revealed as too simple an indicator for argan-forest dynamics, and the first impression of a positive development needs to be revised: The new small trees as well as trees with decreased crown sizes clearly show much stronger degradation characteristics than others, indicating increased pressures on the argan ecosystem during recent decades. Structural traits of the smaller trees also suggest that the apparent increase of tree count is not a result of natural rejuvenation, but mostly of stump re-sprouting, often into multi-stemmed trees, after felling of a tree. The density of the argan forest in the 1960s, prior to the general availability of cooking gas in the region and before the stronger enforcement of the argan logging ban following the declaration of the UNESCO biosphere reserve, may have marked a historic low in our study area, making the baseline of our change analysis far removed from the potential natural state of the argan ecosystem.

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