scholarly journals Structural Characteristics of Natural Limestone Forests in Cat Ba Biosphere Reserves, Vietnam

2020 ◽  
pp. 161-172
Author(s):  
Tran Hai Long ◽  
I. M. Sangjun ◽  
Trieu Thai Hung ◽  
Qiwen Li ◽  
Ninh Viet Khuong ◽  
...  
Keyword(s):  
Species Richness ◽  
Sustainable Forest Management ◽  
Structural Characteristics ◽  
Biosphere Reserve ◽  
Basal Area ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Natural Forests ◽  
Clear Cut ◽  
Anthropogenic Intervention

An ecological understanding of natural forests after anthropogenic intervention is important for sustainable forest management. This study analyzed the overstory characteristics (species composition, growth, and diameter distribution) and regeneration (species richness, density, and height distribution) in natural limestone forests in Cat Ba Biosphere Reserve, Vietnam. Data were collected in nine study plots established in selective-logged (SLF), clear-cut (CCF), and unlogged (UF) forests. Results indicated that the overstory characteristics of SLF and CCF were lower than that of UF (species richness was 33 in UF, 20 in SLF, and 16 in CCF; DBH was 20.6 ±13.7 cm in UF, 16.9 ±9.7 cm in SLF, and 10.5 ±3.8 cm in CCF; Basal area was 38.2 m2 ha-1 in UF, 24.0 m2 ha-1 in SLF, and 11.4 m2 ha-1 in CCF). For regeneration, species richness also varied from UF (25) to SLF (13) and CCF (5), while seedling density reversely increased. We concluded that a 20-year restoration was insufficient for artificially disturbed forests to recover their ecological functions, regardless of logging intensities and techniques applied.

Restoration of Degraded Natural Limestone Forests in Cat Ba Biosphere Reserves, Vietnam

2021 ◽  
pp. 14-26
Author(s):  
Tran Hai Long ◽  
Trieu Thai Hung ◽  
Sangjun Im ◽  
Dang Thi Hai Ha ◽  
Ninh Viet Khuong ◽  
...  
Keyword(s):  
Natural Regeneration ◽  
Forest Restoration ◽  
Forest Cover ◽  
Biosphere Reserve ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Overstory Trees ◽  
Artificial Restoration

Vietnam experienced significant forest cover change during the last half of the twentieth century, and restoration of natural forests have increased since the 1990s. This study developed comparisons of human-intervened and naturally restored forests in Cat Ba Biosphere Reserve, Vietnam in order to gain a better understanding of restoration options for the dual objectives of biodiversity conservation and forest cover. The overstory trees (species composition, growth, and diameter distribution) and natural regeneration (species richness, density, and height distribution) were measured and compared in twelve plots established in natural (NPS) and artificial restoration (RPS) models for post-selective-logged forest, and natural (NPC) and artificial restoration (RPC) models for post-clear-cut forest. Results indicated that the overstory trees and natural regeneration of RPS and RPC was higher than that of NPS and NPC. We concluded that the forest restoration models had shown successes, although extensive silvicultural techniques should be applied for a more stabilized development, especially in the RPC.

INVESTIGATING SILVICULTURAL CHARACTERISTICS OF YEW (TAXUS BACCATA L.) STAND USING FULL-CALLIPERING IN NORTHERN FORESTS OF IRAN

2013 ◽  
Vol 06 (01) ◽  
pp. 1250067 ◽  
Author(s):  
MIR MOZAFFAR FALLAHCHAI ◽  
SEYED ARMIN HASHEMI ◽  
GASEM RAHANJAM
Keyword(s):  
Distribution Curve ◽  
Basal Area ◽  
Diameter Distribution ◽  
Maximum Height ◽  
Taxus Baccata ◽  
Height Distribution ◽  
Annual Increment ◽  
Restricted Area ◽  
Northern Forests ◽  
Low Rate

In this research, some of site and silvicultural characteristics of Yew stand in northern forests of Iran was studied. For this purpose, compartment number 16 of district 4 Shir-ghalaye was selected. According to research purposes, stands with an area of 20 ha were chosen in center of the compartment and was separated from map. Due to restricted area of region and according to few number of Yew trees in the stand, the full-callipering method was conducted for measuring quantitative and qualitative characteristics. In the stand diameter at breast height (D.B.H.), height and canopy diameter of all Yew trees were measured. The results showed that the diameter distribution curve and height distribution curve of Yew trees were similar to even-age forests curve. But according to average annual increment, mixture type of Yew trees in stand, diameter distribution of other species and low rate regeneration of Yew, it can be concluded that the studied Yew stand, is an uneven-age stand and because of low rate regeneration in previous years the number of young Yew trees were reduced and even-age forest curve was formed subsequently. The maximum height and diameter of Yew trees were recorded 26.8 m and 112 cm, respectively. Also, the number of trees per hectare and basal area per hectare of Yew trees were calculated 14.55 and 3.23 m2 respectively.

Structure of mixed pine and hardwood stands 12 years after various methods and intensities of site preparation in the Georgia Piedmont

1996 ◽  
Vol 26 (8) ◽  
pp. 1490-1500 ◽  
Author(s):  
Timothy B. Harrington ◽  
M. Boyd Edwards
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Low Cost ◽  
Basal Area ◽  
Diversity Indices ◽  
Site Preparation ◽  
Clear Cut ◽  
Clear Cutting ◽  
Georgia Piedmont ◽  
Compensatory Effect

In the Georgia Piedmont (U.S.A.), size, abundance, and species diversity of trees were quantified in a plantation of Pinustaeda L. 12 years after various methods and intensities of site preparation. In clear-cut only versus site-prepared plots, greater hardwood abundance (27% vs. 8% of the total basal area) and size (8.6 vs. 7.4 m in height) were associated with reduced pine volume (73 vs. 123 m3/ha) and increased Simpson and Shannon diversity indices. Tree-species richness was greater in plots where residual trees from clear-cutting had been removed with a chainsaw versus large machinery (10 vs. 7 species). With increasing site-preparation intensity, reductions in basal area of volunteer pines coincided with proportionate increases (R2 = 0.80) in basal area of planted pines. As a result of this compensatory effect, total volume of all pines varied little (122–134 m3/ha) among site-preparation intensities. Research results suggest that site-preparation treatments can be selected to facilitate the development of a variety of stand structures, including those that favor evenness (clear-cut only) or richness (manual cutting) of tree species, low-cost production of pine fiber (manual cutting), and stand uniformity for management of pine sawtimber (mechanical and herbicide).

scholarly journals A Structure Analysis for Ecological Management of Moist Tropical Forests

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Adrien Djomo Njepang
Keyword(s):  
Species Composition ◽  
Stand Structure ◽  
Human Impacts ◽  
Basal Area ◽  
Diameter Distribution ◽  
Ecological Management ◽  
Natural Forests ◽  
Forest Types ◽  
Moist Forest ◽  
Commercial Species

Human interventions alter stand structure, species composition, and regeneration capacity of the forest. There is no enough information on how different management systems affect the forest structure. The main objective of this study was to analyze the differences on stand structure and species composition caused by different logging intensities. The study was conducted in a lowland evergreen moist forest of 22 000 ha in Cameroon. The forest was subdivided into three forest types with different human impacts:2-Logged,1-Logged, andUnlogged. The diameter corresponding to mean basal area of stems of2-Logged(31.8 cm,N=369) was almost equal to that ofUnlogged(30.1 cm,N=496).1-Loggedhad a lower diameter of 27.7 cm,N=530. In the three forest types, the diameter distribution followed the inverse J-shaped curve frequently observed in natural forests. The stand basal area increased from 29.4 m2/ha in2-Logged, to 32 m2/ha in1-Logged, and to 35.3 m2/ha inUnlogged. These results indicated that logging affected natural regeneration in2-Logged. Above 60 cm dbh, the logging effect was not visible. On 103 tree species found in the sample forest, only nine were classified as harvestable commercial species.

scholarly journals Structural analysis of mixed stands coming from natural regeneration and plantations after fire

Web Ecology ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 32-37
Author(s):  
T. Tsitsoni ◽  
M. Tsakaldimi ◽  
E. Simeliadou ◽  
M. Fouska
Keyword(s):  
Stand Structure ◽  
Structural Characteristics ◽  
Basal Area ◽  
Stem Diameter ◽  
Diameter Distribution ◽  
Cupressus Sempervirens ◽  
Mixed Stands ◽  
Crown Length ◽  
Stem Quality ◽  
Naturally Regenerated Stands

Abstract. We analyzed the structure and growth of naturally regenerated stands of Pinus brutia that mixed with planted broad-leaved and conifer species, 12 years after wildfire and examined the degree of species mix. Field data on stand structure of P. brutia forest were taken in spring 2009 on northern and southern aspects differing in regeneration conditions. Sixteen sample plots were selected and all individuals and their attributes measured. The results showed that in northern aspects the forest is composed of P. brutia in the over-storey and Quercus pubescens and Cupressus sempervirens in the under-storey, while in southern aspects the forest was mainly composed by P. brutia (81%). Stem diameter distribution of P. brutia in both aspects followed almost a normal pattern. All P. brutia individuals were characterized by vigorous growth and good to normal stem quality. Aspect did not statistically affect structural characteristics of P. brutia trees and saplings. However, on the northern aspect stem diameter, height, crown length and basal area of P. brutia were greater than in the southern aspect. Aspect significantly affected structural characteristics of Q. pubescens.

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 Disentangling structural patterns of natural forest fragments in a savanna matrix in the eastern Brazilian Amazon

2017 ◽  
Vol 47 (2) ◽  
pp. 111-122
Author(s):  
Iêda Leão do AMARAL ◽  
William Ernest MAGNUSSON ◽  
Francisca Dionízia de Almeida MATOS ◽  
Ana Luisa K. ALBERNAZ ◽  
Yuri Oliveira FEITOSA ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Density ◽  
Fragment Size ◽  
Negative Relationship ◽  
Basal Area ◽  
Average Diameter ◽  
Diameter Distribution ◽  
Forest Fragments ◽  
Continuous Forest ◽  
Individual Trees

ABSTRACT Natural fragments are an important source of richness for the management and conservation of a local flora. The objective of this study was to evaluate the effect of fragmentation on the structure and composition of the plant communities of forest fragments (FF) in Alter do Chão, eastern Brazilian Amazonia. The study sample consisted of 25 FF and nine continuous forest (CF) sites. We compared plant density and species richness between site categories by t-tests, analyzed the differences in composition by cluster analysis, and assessed the effect of fragment size and distance to CF on the basal area and diameter of FF assemblages by linear regression. Individual trees and shrubs with DBH ≥1.27 cm were measured in 2x250 m plots. 17,078 individuals were recorded - 75.32% in FF and 24.68% in CF, comprising 475 species, 216 genera and 64 families. Myrtaceae and Fabaceae were the most abundant families in both FF and CF. Average species richness in FF and CF was statistically different. The 20 species with the highest importance values were similar in FF and CF. The average plant diameter was similar in FF and CF, suggesting that both are "mature" forests composed of thin individuals. Average diameter and total basal area showed a negative relationship with distance to CF and fragment area, respectively. Similarity analysis revealed two groups, one composed exclusively of portions of fragmented forest. Fragments and continuous forest differed in species composition, but were similar in structure. Diameter distribution in fragments was similar to that of primary forests.

scholarly journals Struktur Floristik Hutan di Kawasan Lindung Sempadan Sungai dalam Areal Hutan Tanaman Industri

2018 ◽  
Vol 10 (1) ◽  
pp. 24
Author(s):  
Nurul Qomar ◽  
Bahdarsyah Bahdarsyah ◽  
P Agung Nugroho ◽  
Rahmi A Rohaini ◽  
Ahmad Muhammad
Keyword(s):  
Species Richness ◽  
Forest Type ◽  
Diversity Index ◽  
Acacia Mangium ◽  
Basal Area ◽  
Pole Density ◽  
Natural Forests ◽  
Conservation Areas ◽  
Importance Value ◽  
Swamp Forest

This study was carried out in riparian conservation forests within a monospecific pulpwood estate in Sorek,Pelalawan District, Riau. The remaining natural forests comprised lowland rainforest (at Sei Buluh and Tolamriversides), mixed swamp forest (at Telayap riverside), and pole forest (at Rangsang riverside). The objective of thecurrent study was to describe the floristic structure of each forest type at the conservation areas in concern.Fifteen transects (width of 20 m) were established at all sites with a total length of 8.080 m. Quadrates plots of 20x 20 m were established with continue on these transect for tree sampling (dbh > 20 cm) and smaller quadrates(10 x 10 m) were nested on each one of the former for pole sampling (dbh 10 – 20 cm). The parameters used in thisstudy were Importance Value (IV), species richness (Margalef Index = R1 and Menhinick Index = R2), and Diversity Index (Shannon = H’ and Simpson = D). Results showed that in tree stratum, the largest basal area (11.25 m2ha-1) and the highest diversity was found at Telayap’s riverside (H’ = 3.70 and D = 0.98). Species richness was most profound at Tolam riverside (R1 = 10.43 and R2 = 2.83). Rangsang’s riverside possessed the highest tree density (105 individuals ha-1) but with the smallest dbh (26.5 cm). This forest was a peat-swamp forest predominating by bintangur (Calophyllum pulcherimum). At the pole stratum, the largest basal area (7.00 m2ha-1) and the highest diversity was found at Tolam riverside (H’ = 3.39 and D = 0.96). Species richness was most profound at Telayap’s riverside (R1 = 8.89 and R2 = 2.64). The highest pole density (380 individuals ha-1) was observed at Sei Buluh’s riverside, in which mempening (Quercus lucida Roxb.) was predominating. Acacia mangium was establishing very well at all sites, indicating its adaptability and potentially invasive feature.

scholarly journals Ecological and Structural Characteristics of Riparian Forest in Omo Biosphere Reserve

2020 ◽  
Vol 24 (9) ◽  
pp. 1687-1691
Author(s):  
O.R. Olatidoye ◽  
O.J. Oyelowo ◽  
O.D. Akinyemi ◽  
C. Kambai ◽  
A.A. Ayodele
Keyword(s):  
Riparian Forest ◽  
Structural Characteristics ◽  
Biosphere Reserve ◽  
Basal Area ◽  
Riparian Forests ◽  
Diameter Class ◽  
Species Dominance ◽  
The Core ◽  
Class Distribution ◽  
Major River

An investigation on the structural characteristics of the riparian forest in Omo Biosphere Reserve was carried out. The structure was analyzed  through diameter class distribution, basal area and breast height. Riparian forest showed a major characteristic in the physiognomy of forests along major river, streams and Upland vegetation and the Core, Buffer and Transition zones that is highly variable in the diameter class distribution  (reserve J type), Mean basal area per hectare for major river is 294,089.30 cm2/ ha, Stream 613.027 cm2/ha, and Upland 205,648 cm3/ha. Mean basal area for core is 507,399.50 cm2/ha, buffer had 340,699 cm2/ha and transition 264,656 cm2/ha. While mean volume per hectare for core is 7955.2 m3/ha, buffer 7260 m3/ha and Transition 6254.4 m3/ha. Maximum dbh of 246 cm was obtained in the core species. Many stands of riparian forests are facing various levels of structural and floristic simplification, which include fundamental transformations in vegetation physiognomy from dense stands to riparian scrub or bare land. Keyword: Riparian forests, structure, diameter, basal area, species dominance, Omo

scholarly journals Deriving Tree Size Distributions of Tropical Forests from Lidar

2021 ◽  
Vol 13 (1) ◽  
pp. 131
Author(s):  
Franziska Taubert ◽  
Rico Fischer ◽  
Nikolai Knapp ◽  
Andreas Huth
Keyword(s):  
Size Distribution ◽  
Spatial Scales ◽  
Basal Area ◽  
Tree Height ◽  
Tree Size ◽  
Diameter Distribution ◽  
Forest Inventories ◽  
Allometric Relations ◽  
Lidar Measurements ◽  
Derived Data

Remote sensing is an important tool to monitor forests to rapidly detect changes due to global change and other threats. Here, we present a novel methodology to infer the tree size distribution from light detection and ranging (lidar) measurements. Our approach is based on a theoretical leaf–tree matrix derived from allometric relations of trees. Using the leaf–tree matrix, we compute the tree size distribution that fit to the observed leaf area density profile via lidar. To validate our approach, we analyzed the stem diameter distribution of a tropical forest in Panama and compared lidar-derived data with data from forest inventories at different spatial scales (0.04 ha to 50 ha). Our estimates had a high accuracy at scales above 1 ha (1 ha: root mean square error (RMSE) 67.6 trees ha−1/normalized RMSE 18.8%/R² 0.76; 50 ha: 22.8 trees ha−1/6.2%/0.89). Estimates for smaller scales (1-ha to 0.04-ha) were reliably for forests with low height, dense canopy or low tree height heterogeneity. Estimates for the basal area were accurate at the 1-ha scale (RMSE 4.7 tree ha−1, bias 0.8 m² ha−1) but less accurate at smaller scales. Our methodology, further tested at additional sites, provides a useful approach to determine the tree size distribution of forests by integrating information on tree allometries.

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