Point-centered Quarter Method Research Articles

Current status, utilization, succession and zonation of mangrove ecosystem along Mida Creek, Kenya

Abstract. Warui MW, Manohar S, Obade P. 2020. Current status, utilization, succession and zonation of mangrove ecosystem along Mida Creek, Coast Province, Kenya. Bonorowo Wetlands 10: 32-43. Human activities have resulted in the destruction of mangrove forests, posing a threat to the mangrove ecosystem and the living things that rely on it. From September 2009 through February 2010, researchers studied the current state, usage, succession, and zonation of the mangrove ecosystem along Mida Creek in Kenya's Coast Province. The goals were to assess changes in the floristic composition of the mangrove forest, identify the most preferred mangrove species, investigate whether accessibility determines utilization of mangrove species, investigate whether harvesting of mangroves affects their succession, and investigate the effectiveness of current mangrove forest management policies. The data was collected using the Point-Centered Quarter Method (PCQM) to see if access into the mangrove forest influences their use and if mangrove succession is affected by their use. To evaluate the efficiency of government policies/legislation governing mangrove exploitation and the most favored mangrove species by the local community and other users, questionnaires were circulated and interviews were conducted. Out of the 210 houses in Mida Creek, 136 respondents were interviewed, one from each household. To examine the temporal changes in the floristic composition of the mangrove forest, two sets of aerial images (1992 and 2006) were processed and interpreted. The data from the questionnaires were coded and entered into the Statistical Package for the Social Sciences (SPSS). An analysis of variance (ANOVA) was used to see if the accessibility of mangroves influences their use. To see if the utilization of mangroves affects their succession, researchers used regression analysis. To evaluate the forest structure, an importance value was derived. To summarize the present mangrove forest management policies and their effectiveness, descriptive statistics were used. Between 1992 and 2006, the floristic composition of the mangrove forest in Mida Creek changed; the area covered by mangroves decreased as follows: Rhizophora mucronata (Rm); 65.09-63.93ha; Avicennia marina (Am); 344.99-310.63ha; Ceriops tagal (Ct); 225.12-223.82ha; Rm and Ct; 52.87-50.22ha; Ct and Am; 143.69- 140.29ha; Rm and Am; 44.36-41.27ha; Rm and Bg; 212.75-199.75ha; Rm and Sonneratia alba (Sa); 47.64-46.32ha; Rm, Ct and Bruguiera gymnorrhiza (Bg); 129.07-128.12ha; Rm, Am, Ct, and Bg; 472.44-428.46ha. The number of cut mangroves in the adjacent settlements, center, and shoreline revealed a significant difference (F=3.277; df=2; p=0.040) in the ANOVA test, indicating that accessibility determines consumption. The most favored mangrove species was Rhizophora mucronata, according to the findings. There was a correlation between the number of mangrove seedlings and the number of cut mangroves (F=8.529, df=1, R=0.198, P=0.004), according to regression analysis. The use of mangroves has an impact on their succession. Mangrove utilization policies and legislation have been less effective. The key species in Mida Creek were Rhizophora mucronata and Ceriops tagal. The extent of mangrove forests in Mida Creek has shrunk over time.

Species composition and forest conditions of true mangroves in Kapa at Kadan Island, Myeik Archipelago, Myanmar

The survey was conducted in the mangrove forest around the Kapa Village in Kadan Island, Myeik Coastal area, in April 2018. Transect lines in shoreline, seaward and landward, and plot based on Point Center Quarter Method (PCQM) P-DATA PRO were used. A total of 18 species of true mangroves were record. Among than 1 species in Near Threaten(NT), 1 species in Critically Endangered(CR), 2 species in Endangered(EN) considered under the IUCN red list. Rhizophora apiculata and R.mucronata are the dominant species in the area. Aegialitis rotumdifolia, Avicennia marina, Excoecaria aglocha, Heritiera littoralis, Sonneratia graffithii, Xylocarpus mucronata and Nypa fruticans are the least species in the area. Among the three study sites of Kapa, Landward zone is the most distributed of species and shoreline zone is the least distributed. The complexity index was found 2.5 to 67.3.The total forest density 0.17 to 0.39m2 and mean height 3.2 to 4.7m. The mean important value of Rhizophora apiculata was heights; the Nypa frucan was least. The environmental parameters such as salinity and temperature of seawater, and temperature and pH of soils of each study site were presented.

Vegetation analysis of highland tropical rainforest in the conservation area

Nature protection and preservation in Indonesia is carried out by designating certain places as nature reserves. One area that has been chosen as a nature reserve in East Java is the Mount Sigogor Nature Reserve, with the most extensive type of mountain tropical rainforest in the area. The purpose of this study was to determine the composition of species at the level of trees and species dominant in mountain tropical rainforests. Data collection method uses the quadrant method (Point Center Quarter Method). Relationship analysis uses the 2 × 2 Contingency Table method. Based on the results of the study, it founded that the vegetation of Mount Sigogor Nature Reserve consisted of at least 47 tree species including 23 families dominated by couples (Quercus sondaica BL Miq) with INP of 37.93%. The next sequence was Dodonea viscosa with INP of 35.90% followed by Casuarina sp with INP of 28.21%, Litsea glutinosa and Persea odoratissima (Nees) Kosterm with INP of 27.11% and 16.29% respectively. The pair of species that tend to live together is Quercus sondaica with Litsea glutinosa.

Structure and temporal changes in the mangrove vegetation of Jambusar Taluka of Gulf of Khambhat, India

The objective of the present investigation was to assess the structure and the temporal changes in the mangrove cover of Jambusar Taluka of Bharuch district of Gujarat State, India. This was accomplished by conducting phytosociology surveys using the Point-Centered Quarter method and by analyzing satellite images. The satellite images covering a time scale of more than 30 years (1978–2012) and topographic sheets (1973–1977) prepared by Survey of India were analyzed to map and to bring out the changes in the mangrove cover. ERDAS Imagine (V.9.1) and ESRI’s ArcInfo (User 7.2.1) software was used to carry out the image analysis as well as the change detection study. The results showed that only one species of true mangrove i.e. Avicennia marina was present in the area. The phytosociological survey revealed that the stem density at Jamdi and Devla was 5189 and 30,795 stems/ha respectively. The mangrove extent which was 279.87 ha in 1978 had increased to 1298.26 ha in 2012. Natural regeneration and plantation activities carried out by various agencies were the major reasons for this increase. The change detection analysis however revealed high rates of mangrove loss in the southern part of the taluka.

La rehabilitación forestal y su papel en la conservación avifaunística en El Porvenir, Hidalgo, México

Introduction: Conserving terrestrial ecosystems in good condition is a global challenge. In Mexico, forest rehabilitation is a widely used practice to achieve this task. Objective: To analyze the effect of forest rehabilitation on avifauna parameters (richness, abundance and diversity) and vegetation structure. Materials and methods: The study was conducted in El Porvenir, Hidalgo, Mexico, in areas under forest rehabilitation with Pinus greggii Engelm. ex Parl. aged 5(R5), 12(R12) and 14(R14) years, and in a Pinus cembroides Zucc. forest as a reference site (RS). Sampling was done using a systematic grid design. Avifauna presence was monitored under two schemes: fixed-radius point counts and capture by constant-effort mist-netting. The tree structure was characterized by the point-centered quarter method. Differences between conditions were tested with a permutational multivariate analysis of variance (PERMANOVA). Results and discussion: The RS had the highest bird richness (34) and showed significant differences (P = 0.0003) with rehabilitation conditions. The distribution of abundance in R5 and R14 was fitted to a geometric model, R12 to a logarithmic model and RS to a log-normal one, exhibiting significant differences among them (P = 0.033). Bird diversity presented differences between conditions (P = 0.005); the maximum similarity was between R14 and RS. The older the forest rehabilitation age, the more the vegetation structure and bird parameters increased. Conclusion: The areas under forest rehabilitation function as reservoirs for the maintenance and conservation of avifauna in disturbed environments.

IDENTIFIKASI JENIS POHON SARANG DAN PAKAN ORANGUTAN (Pongo pygmaeus) DI ARBORETUM NYARU MENTENG, PALANGKA RAYA (Identification of Trees as Nest and Food of Orangutan (Pongo pygmaeus) at the Arboretum of Nyaru Menteng, Palangka Raya)

ABSTRACT This research was aimed to know some trees that used to nest and food of orang utan (Pongo pygmaeus) at the arboretum of Nyaru Menteng in Palangka Raya City. Analysis of vegetation using Point Centered Quarter Method with 23 sample points at the field. Collected data at the August 2017 were founded 25 species of trees, from16 family, whereas 17 trees were used as nest and food and 8 trees were used as nest only. The distance between each tree to measuring point was 3,71 m. Density of the trees namely 726 trees ha-1, with domination namely 28.37, frequency namely 3.48. The important value index of hangkang (Palaquium leiocarpum) was highest, namely 51.91%. Summed dominance ratio namely 17.3 %. Diversity index was moderate with value namely 2.81. Evenness index was high with value namely 0.87.
 Keywords: Food, nest, Nyaru Menteng, Pongo pygmaeus

Composition and diversity of bat assemblages at Arabuko-Sokoke Forest and the adjacent farmlands, Kenya

Abstract Recognized as a global biodiversity hotspot, coastal forests in eastern Africa are currently reduced to fragments amidst human modified habitats. Managing for biodiversity depends on our understanding of how many and which species can persist in these modified areas. Aiming at clarifying how habitat structure changes affect bat assemblage composition and richness, we used ground-level mist nets at Arabuko-Sokoke Forest (ASF) and adjacent farmlands. Habitat structure was assessed using the point-centered quarter (PCQ) method at 210 points per habitat. We captured a total of 24 bat species (ASF: 19, farmlands: 23) and 5217 individuals (ASF: 19.1%, farmlands: 82.9%). Bat diversity was higher at ASF (H′, ASF: 1.48 ± 0.2, farm: 1.33 ± 0.1), but bat richness and abundance were higher in farmlands [Chao1, ASF: 19 (19–25), farmlands: 24 (24–32) species (95% confidence interval [CI])]. Understory vegetation and canopy cover were highest at ASF and the lower bat richness and abundance observed may be the result of the under-sampling of many clutter tolerant and high flying species. Future surveys should combine different methods of capture and acoustic surveys to comprehensively sample bats at ASF. Nonetheless, the rich bat assemblages observed in farmlands around ASF should be valued and landowners encouraged to maintain orchards on their farms.

Ecological Determinants of Species Richness and Abundance of Endemic and Threatened Owls in the Andaman Islands, India

Factors that influence the distribution and abundance of the endemic and threatened owls of the Andaman Islands have not been assessed, in contrast to those affecting diurnal birds. Such studies would assist in prioritising habitats that have high conservation importance for owls. We evaluated the status and species composition of owls along c. 343km of the Andaman Trunk Road, employing one-time point counts between December 2013 and April 2015. We conducted spontaneous listening, broadcasting of conspecific calls and spotlight searches as survey protocols. The pointcentred quarter method was used to evaluate the habitat at each count site. We recorded five owl species whose mean abundance was 2.09 owls/point. Species richness and abundance were greater in unlogged sites and deciduous forests. Habitat differences between owl species were noted according to land use, cover type and intensity of logging activity. However, these factors had no significant effect on the abundance of Oriental Scops-owl and Hume's Boobook, but were significant for Andaman Boobook and Andaman Scops-owl. Mean understory height, tree height and grass cover positively influenced the owl species richness and abundance. The Andaman Boobook and Andaman Scops-owl appeared stenotopic in habitat use and in contrast to the eurytopic Oriental Scops-owl and Hume's Boobook. A review of the conservation status of Andaman Scops-owl and Andaman Boobook is suggested bearing in mind their low abundance, restricted distribution and less preference for altered habitats.–Babu, S., Sureshmarimuthu, S. & Kumara, H.N. (2019). Ecological determinants of species richness and abundance of endemic and threatened owls in the Andaman Islands, India.Ardeola, 66: 89-100.

Vegetation analysis of tree communities at some forest patches in North Sulawesi, Indonesia

Abstract. Siregar M, Helmanto H, Rakhmawati SU. 2019. Vegetation analysis of tree communities at some forest patches in North Sulawesi, Indonesia. Biodiversitas 20: 643-655. Deforestation has caused a decline in forest area in Indonesia. Now natural forests is left in the conservation areas while those outside conservation areas are narrow and fragmented. This study aims to analyze forest vegetation and conservation status of the species of trees in some forest patches in North Sulawesi. Diversity, structure and type of tree communities at five forest patches, namely in the villages of Bukaka, Garini and Lambak in East Bolaang Mongondow District, and Soyowan and Basaan villages in Southeast Minahasa District, North Sulawesi Province were studied using a point center quarter method. The total number of tree species (dbh ≥ 10 cm) across five patches is 84 species. The highest number of species is in Garini (37 species), followed by Lambak (25 species), Soyowan (19 species), Bukaka (10 species) and Basaan (7 species). The species diversity index also shows the same pattern with such species richness, but the dominance index demonstrates opposite trend. The highest evenness index (E) is found in Bukaka (E = 0.9524), followed by Soyowan (E = 0.9061), Garini (E = 0.7873), Basaan (E = 0.7809) and Lambak (E = 0.7099). The most important tree species based on the Species Important Value (SIV) in Bukaka is Ficus sp. (SIV = 52.17), in Garini is Octomeles sumatrana (SIV = 25.73), in Lambak is Boehmeria cylindrica (SIV = 65.03), both in Basaan and Soyowan is Dracontomelon dao with SIV of 96.87 and 46.46 respectively. The beta diversity analyzed based on species similarity index of Jaccard and Whittaker 's index shows a relatively large change in species composition from one location to another. The family of Moraceae, Malvaceae, Anacardiaceae, Annonaceae and Lauraceae are listed as the widest family with a relatively high population. The highest tree density is found in Bukaka (721 trees ha-1), followed by Lambak (482 trees ha-1), Basaan (439 trees ha-1), Garini (292 trees ha-1) and Soyowan (164 trees ha-1). The highest basal area is also found in Garini (53.59 m2 ha-1), followed by Basaan (51.62 m2 ha-1), Lambak (30.74 m2 ha-1), Soyowan (25.13 m2 ha-1) and Bukaka (20.98 m2 ha-1). The results of Cluster analysis using data of species abundance indicate that the five research locations tend to form two types of tree communities. The first community consists of Garini, Soyowan, Lambak and Bukaka, while the second community is represented only by Basaan.

Keanekaragaman Jenis Vegetasi Strata Semak di Hutan Perlindungan Kawasan Bukit Cogong

The research aims at (1) finding the diversity index (H') of bushes vegetation stratum, and (2) abiotic environment factors at Cogong hill. This research used plotless method with Point Centered Quarter Method by classifying into three scopes, namely, research scope A, B and C with 10 items each. Based on the result, the diversity index average (H') of bushes vegetation stratum at Cogong hill in research scope A was 2,13; scope B was 1,77 and scope C was 1,61. The air temperature at Cogong hill was between 28,30C-300C, the air humidity was between 86 % - 93 %, the soil temperature was between 27,30C-29,60C, the soil humidity was between 8% - 17 % and the soil scale of acidity (pH) was between 6,3-6,7. In conclusion, the average of H' in scope A, B, and C was in medium-abundant category. 
 Keywords : diversity , bushes stratum, protected forests, cogong hill

Do abandoned farmlands promote spread of invasive alien plants? Change detection analysis of black wattle in montane grasslands of the Eastern Cape

ABSTRACTInvasive alien plants (IAPs) pose a threat to ecosystem integrity and generally provide more disservices than services. Acacia mearnsii (black wattle) was introduced to South Africa for its provisioning and economic potential. Since then, it has colonized large areas and it is a high priority taxon by the Working for Water (WfW) programme. This study establishes the nature of the spread of A. mearnsii in grasslands in the Eastern Cape Province of South Africa, with the aim of providing feedback to the WfW programme on IAP expansion and focal areas of concern. Land cover change detection analysis using historical aerial photographs showed that A. mearnsii has spread more extensively into disturbed (abandoned cultivation and overgrazed) grasslands compared to undisturbed natural grasslands from the initial plantings prior to 1958. Using the point-centred quarter method to determine density, and an allometric equation to determine above-ground biomass, a growth model for A. mearnsii was prepared. The incremental annual increase in the standing biomass of A. mearnsii using the model, validated against MODIS Net Primary Productivity data, was estimated to be ~10.5 ton DM ha−1 yr−1. The spread rate of wattle maybe up to 10% and several alternative control strategies need to be considered.

Ecological Effects of Road De-Icing Salt on Adirondack Forests and Headwater Streams

We collected water samples from upstream and downstream sites over 3 years on 18 study streams in the Adirondacks, NY, and conducted analysis via ANOVA for the presence of road-salt runoff, as measured by chloride ion content. Streams crossed by state roads received more road-salt runoff than streams crossed by county roads, as shown by higher mean chloride loads across different sampling years (P ≤ 0.01). The chloride load in streams was not reliably higher downstream from a road as opposed to upstream from a road for either state or county roads but varied in different sampling years (P 0.05). We collected a total of 1259 nymphs of Ephemeroptera, Plecoptera, and Trichoptera during water sampling. High levels of road-salt runoff were not associated with lower levels of Plecoptera or Trichoptera. Neither numbers of individuals nor numbers of genera of Ephemeroptera, Plecoptera, or Trichoptera collected per month showed any pattern when regressed on stream-chloride level. However, we detected no Ephemeroptera above a relatively high level of road-salt runoff (154 mg/L chloride ion). We employed the point-centered quarter method to assess forest composition on 10 transects above and below state roads. We conducted further analysis on trees in the lowest quartile of circumference in each transect as a representation of tree-species recruitment. Mean chloride-ion content of study streams, indicating adjacent forest exposure to road-salt runoff, was associated with greater recruitment of Abies balsamea (Balsam Fir), and lower Shannon–Weiner diversity. At the highest chloride levels, there was almost no recruitment of any species but Balsam Fir. Soil-cation analysis and linear regression, however, did not indicate concomitant depletion of plant nutrients, and therefore, we did not confirm the cause of the apparent relationship between higher road-salt runoff and higher Balsam Fir recruitment.

Efecto de los incendios y la elevación en la regeneración de Pinus hartwegii Lindl. en el noreste de México

Introduction: Fire regimes and climate change affect the regeneration of vegetation, composition and abundance of species. Objectives: To compare P. hartwegii regeneration and the number of trees with fire scars at different elevations; and determine whether regeneration is related to the density of adult trees and to the density of pine trees with fire evidence. Materials and methods: P. hartwegii regeneration was studied at the altitudinal ranges 3 050, 3 225 and 3 400 m in the mountain El Potosi located in northeastern Mexico. Adult trees were sampled using the point-centered quarter method and saplings on square plots. Results and discussion: Density of adult pine trees and seedlings was higher at the low elevations (3 050 and 3 225 m). Density of pine trees with fire scars was similar (P > 0.05) at the three elevations. No correlation was detected between regeneration and number of pine trees with fire scars, but there was a positive correlation between density of seedlings and that of adult pines Conclusion: Altitude influences regeneration and density of P. hartwegii adult trees. Its regeneration is not related to fire evidence.

Status of the undisturbed mangroves at Brunei Bay, East Malaysia: a preliminary assessment based on remote sensing and ground-truth observations.

Brunei Bay, which receives freshwater discharge from four major rivers, namely Limbang, Sundar, Weston and Menumbok, hosts a luxuriant mangrove cover in East Malaysia. However, this relatively undisturbed mangrove forest has been less scientifically explored, especially in terms of vegetation structure, ecosystem services and functioning, and land-use/cover changes. In the present study, mangrove areal extent together with species composition and distribution at the four notified estuaries was evaluated through remote sensing (Advanced Land Observation Satellite—ALOS) and ground-truth (Point-Centred Quarter Method—PCQM) observations. As of 2010, the total mangrove cover was found to be ca. 35,183.74 ha, of which Weston and Menumbok occupied more than two-folds (58%), followed by Sundar (27%) and Limbang (15%). The medium resolution ALOS data were efficient for mapping dominant mangrove species such as Nypa fruticans, Rhizophora apiculata, Sonneratia caseolaris, S. alba and Xylocarpus granatum in the vicinity (accuracy: 80%). The PCQM estimates found a higher basal area at Limbang and Menumbok—suggestive of more mature vegetation, compared to Sundar and Weston. Mangrove stand structural complexity (derived from the complexity index) was also high in the order of Limbang > Menumbok > Sundar > Weston and supporting the perspective of less/undisturbed vegetation at two former locations. Both remote sensing and ground-truth observations have complementarily represented the distribution of Sonneratia spp. as pioneer vegetation at shallow river mouths, N. fruticans in the areas of strong freshwater discharge, R. apiculata in the areas of strong neritic incursion and X. granatum at interior/elevated grounds. The results from this study would be able to serve as strong baseline data for future mangrove investigations at Brunei Bay, including for monitoring and management purposes locally at present.

The regenerating forest of Magbukún Aeta in Morong Bataan, Philippines: A Biological Hotspot for Protection and Conservation

This research focused on the study of a tropical semi-evergreen rain forest community structure within the ancestral domain of the Aetas in Morong, Bataan. Point-Centered Quarter Method (PCQM) was used where five 200 m transects were laid across a 28-ha study site. Trees with ≥1cm diameter at 1.3 m from the ground (Diameter at breast height (DBH)) were sampled. Trees encountered were categorized into four groups: seedlings, saplings, pole trees and standard trees based on girth classes. A total of 76 tree species belonging to 61 genera and 35 families were recorded. The most represented family was Moraceae, followed by Dipterocarpaceae, Sapindaceae and Lauraceae. The species with highest importance percentage (IP) were Shorea contorta Vidal (Dipterocarpaceae) (IP=9.731), Macaranga tanarius (L.) Muell.-Arg (Euphorbiaceae) (IP= 5.659) and Canarium europhyllum G. Perkins (Burseraceae) (IP= 4.538). Very high values of species diversity were calculated (H’= 3.817; D’= 0.968). The area was previously a dipterocarp forest and can now be classified as a young regenerating forest, composed primarily of seedlings many of which are dipterocarps. There were 17 threatened species, including two critically endangered and two endangered species (listed in The IUCN Red List of Threatened Species (2017-3) and DAO (2017-11) as well as twelve endemic species identified as present in the area. This forest is a biological hotspot that needs utmost protection and conservation.

Forest Structure and the Species Composition of the Parque Estadual Mata Atlântica, Located in Goiás State, Brazil

The Parque Estadual Mata Atlântica (PEMA), Goiás state, Brazil, is an Atlantic Forest reserve which has not been studied yet. The aims were to investigate plant biodiversity and characterize the flora to support the management plan. We adopt the point-centered quarter method to inventory the tree-shrub and lianas with the diameter at breast height more than or equal to 5 cm. The study was performed through 1.86 km of transect with 187 sampled points. We sampled 748 individuals and identified 109 species, 82 genera, and 51 families. The Shannon-Wiener diversity index (H′) was 3.97, and Pielou’s evenness (J) was 0.846, both considered high. The Fabaceae family was the most diverse with 20 species. Aspidosperma polyneuron, an endangered tree species, had greater relative dominance and importance value. The floristic similarity analysis indicated that the PEMA vegetation belongs to the seasonal forest, currently very fragmented and degraded. Due to several anthropogenic threats, we suggest the following recommendations: prevent the exploitation of species, avoid hunting, control invasive grasses, prevent forest fires, and promote environmental education. This study demonstrates the importance of PEMA for species conservation. Therefore, this study is essential for the development of management plan and the conservation of PEMA biodiversity.

English

Rahim S, Baderan DWK, Hamidun MS. 2017. The density, composition and mangrove forest habitat in coastal areas of Torosiaje Jaya Village, Gorontalo, Indonesia. Bonorowo Wetlands 7: 38-42. The ecosystem of mangrove is a quite good ecosystem which is located in Torosiaje Jaya Village of Popayato Subdistrict, Pohuwato District, Gorontalo Province, Indonesia. This because of the beach in the coastal of Torosiaje Jaya Village is a gently sloping beach. Further, this beach has deposited sediment and it is formed a promontory grave that causes that mangrove in that region grows large and relatively fertile. In addition, the mangrove which is located in Pohuwato has fairly high various species. One of them is found from Avicenniaceae family namely Avicennia marina (Forsk.) Vierh. This study aims to (i) obtain the information about the density of the mangrove; (ii) to determine the composition of mangrove species in coastal areas of Torosiaje Jaya Village; and (iii) to know the habitat of the species which is found in coastal areas Torosiaje Jaya Village. Besides, the data were collected by purposive sampling. Moreover, for the measurement of density, distribution type, diameter trees, and mangrove vegetation height use a distance method (Point-Centered Quarter Method). Further, the composition types of views are based on the number species are found, and to obtain the data of the habitat conditions of the species which has discovered is using a direct observation in the field by a tree and laboratory test sample originating from soil samples in the study sites. Moreover, the result of this study finds the four species of tree which dominates the mangrove in Torosiaje Jaya Village. They are Bruguiera gymnorrhiza, Rhizophora mucronata, Rhizophora apiculata, and Rhizophora stylosa with a density value of 51.55 trees/3 ha with an average distance of 581.94 m/tree. B. gymnorrhiza and R. mucronata are species that dominate in the region due to supply mud as suitable habitat with its growth, besides it is affected by the substrate of mangroves in the Torosiaje Jaya Village it is also affected by salinity and temperature. Further, the data which have obtained, they can be used in a management of mangrove forest which located in the coastal of Torosiaje Jaya Village and they can also be data in mangrove conservation efforts in order to reduce the effects of global warming.

Agricultural history drives structure and tree species composition of second growth forest over 100 years in southeastern Ohio, USA

AbstractQuestionMost modern forest in eastern North America has recolonized after abandonment from agriculture. Cultivation and pasturing, historically the dominant forms of agriculture, differ in their environmental legacies and potentially influence stand development following abandonment. We ask how the legacy of agriculture plays out in development of second‐growth stands, and whether tree community composition and structure differ between sites with contrasting land‐use histories.LocationSoutheast Ohio, USA.MethodsThirty‐five second‐growth stands were sorted into a replicated chronosequence of formerly cultivated and pastured sites spanning 80 yr. Stand age and land‐use history were determined from historical aerial photographs and from site characteristics including microtopography and soil profiles. In addition, a control group was selected consisting of long‐established forest stands showing no signs of agricultural disturbance. At each site stand composition and structure were described using the point‐centred quarter method.ResultsStand density declined and basal area increased through the chronosequence but neither pastured nor cultivated sites reached levels observed in the control group. Density decreased most dramatically between the 41–60‐ and 61–80‐yr age classes, consistent with competitive stand thinning. Tree community composition changed through time, reflecting a shift away from light‐demanding successional species and toward long‐lived, shade‐tolerant species characteristic of long‐established forests. Composition and structure did not differ significantly between cultivated and pastured sites, but individual species did show significant differences, with the greatest contrast evident shortly after abandonment.ConclusionsStand development following agriculture appears to be a process of convergence in species composition and density. Because most deciduous forest in eastern North America is <80‐yr‐old, these results suggest that most forest is still accruing biomass and has yet to reach a stable density and composition.

Comparison ofT-Square, Point Centered Quarter, andN-Tree Sampling Methods inPittosporum undulatumInvaded Woodlands

Tree density is an important parameter affecting ecosystems functions and management decisions, while tree distribution patterns affect sampling design.Pittosporum undulatumstands in the Azores are being targeted with a biomass valorization program, for which efficient tree density estimators are required. We comparedT-Square sampling, Point Centered Quarter Method (PCQM), andN-tree sampling with benchmark quadrat (QD) sampling in six 900 m2plots established atP. undulatumstands in São Miguel Island. A total of 15 estimators were tested using a data resampling approach. The estimated density range (344–5056 trees/ha) was found to agree with previous studies using PCQM only. Although with a tendency to underestimate tree density (in comparison with QD), overall,T-Square sampling appeared to be the most accurate and precise method, followed by PCQM. Tree distribution pattern was found to be slightly aggregated in 4 of the 6 stands. Considering (1) the low level of bias and high precision, (2) the consistency among three estimators, (3) the possibility of use with aggregated patterns, and (4) the possibility of obtaining a larger number of independent tree parameter estimates, we recommend the use ofT-Square sampling inP. undulatumstands within the framework of a biomass valorization program.

A Geospatial Analysis of Bark Beetle-Induced Wildfire Risk Zones in the Okanogan Wenatchee National Forest

Over the past 30 years mountain pine beetle (MPB) outbreaks have become widespread throughout the western US and Canada. MPB attacks leave acres of dead trees that may predispose forest landscapes to large fires. With the use of field work and geospatial technology, these outbreaks can be better mapped and assessed to evaluate forest health. This study is designed to map and classify bark beetle infestation in Washington's Wenatchee National Forest. Field work on seventeen randomly selected sites was conducted using the point-centered quarter method. Recent MPB outbreak areas were classified using National Agriculture Imagery Program (NAIP) imagery. A link between MPB attack and forest fires was then quantified using MODIS fire data. Lastly, a predictive infestation model was constructed using the following geophysical parameters: disturbance indices, Landsat TM5 classification of groundcover as well as vegetation stress using hyperspectral data. Selected imagery from the Hyperion sensor was used to run a minimum distance supervised classification in ENVI, in attempt to detect the early “green stage” of infestation. This study detected MPB spread and assessed the fire risk related to infestation.