Does the severity of a forest fire modify the composition, diversity and structure of temperate forests in Jalisco?

Introduction: Forest fires are natural disturbances that influence structure, dynamics, performance, composition and diversity of species. Objective: To compare composition, structure and diversity of temperate forest vegetation affected by different levels of severity of a forest fire in Jalisco. Materials and methods: Composition, horizontal structure, importance value index (IVI), diameter class, diversity indexes of Shannon, Simpson, Margalef richness and Bray-Curtis similarity were evaluated in three regions (Bosque La Primavera and Sierra de Tapalpa and Sierra de Quila) of temperate forest with three levels of severity (no fire, moderate and extreme). Results: Twelve species from six families were recorded. Pinaceae and Fagaceae were the most dominant. Dominance ranged from 0.2 to 50 m2∙ha-1 in moderate and extreme severity sites. Pinus devoniana recorded the highest IVI (71 %) in Sierra de Tapalpa. The highest number of trees was recorded in diameter class ≤30 cm. Diversity and richness indices showed significant differences (P < 0.05) for Sierra de Tapalpa and Sierra de Quila and among fire levels; the highest indices were recorded in sites of moderate severity. Tree composition similarity between regions was low (<33 %). Conclusions: Moderate severity of forest fire favored composition, structure and diversity of vegetation in temperate forests of Jalisco, indicating that the level of severity influences resilience of forest ecosystem communities.

EFFECT OF STEM DIAMETER, MEDIA TYPE AND LIGHT INTENSITY ON THE GROWTH OF MEDICINAL PLANT OF SCREW TREE/KAYU ULES (Helicteres isora Linn.)

Screw tree (Helicteres isora) is a shrub species (Fam: Malvaceae) with 1.5–4 m in height and with multi-main trunks up to 9–12. In Indonesia, kayu ules has been used as a traditional medicine, known as jamu, and has been commercialized. In order to cultivate this species, vegetative propagation is likely promising compared to the generative propagation since seed viability is low and cannot be stored for longterm. Nevertheless, there is a lack of information on which diameter classes, media types and light intensities would give the best result for vegetative propagation. This research aimed to obtain information on which diameter classes and media that were suitable for kayu ules stem cutting propagation and to what degree the light intensity would be best for the growth of the seedlings of kayu ules. Three diameter classes and four media types were employed in a complete random design under the greenhouse environment. Three months old good quality vegetatively-propagated seedlings were transplanted under two light intensities (under transparent canopy and shading net). The result showed that considering the factor of diameter classes and media in kayu ules stem cutting propagation, it had improved the survival of the stem cutting. Diameter class I was best grown in media type 3 with 46.67 ± 12.2 % of survival rate, diameter class II was best grown in media type 2 with 38.67 ± 11.6 % of survival rate, whereas diameter class III was best grown in media type 4 with 52 ± 6.9 % of survival rate. The transplanted seedlings also grew significantly better under transparent canopy with higher light intensity. The distinctive features of screw tree under shading net were wider leaf area, higher specific leaf area and relative water content but it was lower in above ground dry biomass compared to the kayu ules under transparent canopy.

Structure of Plants across Habitat Types in Amurum Forest Reserve, Plateau State Nigeria

The Amurum Forest Reserve is one of the nature reserves in Plateau State North central Nigeria. Strict Nature reserve is prominent among the methods for in situ conservation of biodiversity in Nigeria and also the world at large. A study was conducted in the Forest across three habitat types in order to measure tree height and diameter at breast height (dbh) of trees. 50m x 50m plots were marked across the habitat types by simple random sampling technique. Trees and shrubs were identified to species level. Measurement were limited to all woody plants with diameter at breast height (dbh) of ≥ 10cm. Data collected was analyzed in excel. A total of 397 woody species were identified during the study period. 87.7 of the plants were shrubs while 12.3% were trees. The gallery forest had the highest diameter class(30-35cm) followed by the savanna(25-30cm) and lastly the rocky outcrop with the diameter class of 20-25cm.The rocky outcrop had the highest number of trees with the lowest dbh (10-15cm) while the gallery forest had more trees in the highest diameter class (30-35) (Figure 2). The highest mean height distribution in the Gallery forest shows that the plant communities in this habitat type has grown over the years without disturbance since the place is a protected site. Therefore, other surrounding bushes should be protected in order to preserve species from local extinction.

Effect of spacing on volume, form factor and taper for Pinus taeda trees in Paraná, Brazil

Several forestry procedures affect tree volume and shape, such as spacing, pruning, and thinning. Studying and understanding the effect of these operations on stand attributes are very important for forest management. This study aimed to evaluate volume, form factor, and taper for Pinus taeda trees stratified into diameter classes within two planting spacings. In addition, we aimed to evaluate the time spent to scale each tree, measured with a chronometer. Indirect scaling was performed using a Criterion RD 1000. Thirty trees were scaled on each planting spacing (3 m x 2 m and 4 m x 2 m), totaling 60 trees encompassing all diameter classes. Tree volume was calculated using the Smalian equation. Tree volume, form factor, and taper were calculated to each tree and evaluated by stand (independent t-test) and diameter class (variance analysis and Tukey test). The average scaling time was 4 minutes and 35 seconds, which decreased with practice (-24%). Form factor and taper differed with spacing and diameter class. Volume did not differ with spacing, but it did in the diameter classes. We concluded that indirect scaling is a practical method for tree volume assessment; higher planting density leads to more cylindrical stems with lower taper ratios in comparison with denser stands; and the fact that tree volume, form factor and taper differed among the diameter classes should be incorporated into studies of taper modeling.

Determination of the biomass stock in a mixed plantation of Pinus taeda L. and Pinus elliottii Engelm.

Mixed planting when well managed can be more efficient in the production of biomass and in the use of available resources, thus increasing the profits of planting. The objectives of this research were to quantify the biomass of a mixed plantation of Pinus taeda and Pinus elliottii, by the direct method and to verify the allocation of biomass between the components and the production of biomass per unit area of the mixed plantation and of the two species studied. From the forest census carried out in the mixed planting of 43.5 ha, at 16 years of age, the diametric distribution of the population was generated. Based on the diametric classes, 60 trees were randomly sampled by the direct method, 30 trees for each species. Then, the aerial biomass production in the different components of the tree for both species was evaluated and compared. Mixed planting produced 171.5 t ha-1 of biomass; the shaft represented more than 60% of the biomass. The biomass production in Pinus taeda was superior to Pinus elliottii. The biomass of branches, in turn, was significantly different between species. The stratified tree technique revealed that biomass production in the stand was lower than the biomass obtained by the direct method. In this technique, the biomass (t ha-1) was superior to Pinus elliottii, due to the frequency of individuals in the forest census being higher in the central diameter class, and the species having a larger number of individuals in the stand.

How to Evaluate Downed Fine Woody Debris Including Logging Residues?

Volume or biomass estimates of downed woody debris are crucial for numerous applications such as forest carbon stock assessment, biodiversity assessments, and more recently for environmental evaluations of biofuel harvesting practices. Both fixed-area sampling (FAS) and line-intersect sampling (LIS) are used in forest inventories and ecological studies because they are unbiased and accurate methods. Nevertheless, most studies and inventories take into account only coarse woody debris (CWD, >10 cm in diameter), although fine woody debris (FWD) can account for a large part of the total downed biomass. We compared the LIS and FAS methods for FWD volume or biomass estimates and evaluated the influence of diameter and wood density measurements, plot number and size. We used a Test Zone (a defined surface area where a complete inventory was carried out, in addition to FAS and LIS), a Pilot Stand (a forest stand where both LIS and FAS methods were applied) and results from 10 field inventories in deciduous temperate forest stands with various conditions and amounts of FWD. Both methods, FAS and LIS, provided accurate (in trueness and precision) volume estimates, but LIS proved to be the more efficient. Diameter measurement was the main source of error: using the mean diameter, even by diameter class, led to an error for volume estimates of around 35%. On the contrary, wood density measurements can be simplified without much influence on the accuracy of biomass estimates (use of mean density by diameter class). We show that the length and number of transects greatly influences the estimates, and that it is better to apply more, shorter transects than fewer, longer ones. Finally, we determined the optimal methodology and propose a simplification of some measurements to obtain the best time-precision trade-off for FWD inventories at the stand level.

Characteristics, Floristic Diversity and Structures of Stands Resulting from Assisted Natural Regeneration (ANR) in the Agroecozone of Tibiri in Niger

The present study was carried out in the municipality of Tibiri where assisted natural regeneration is the method adapted by agriculture to maintain trees for various reasons. The general objective of this study is to characterize the floristic diversity and the structure of the woody stand resulting from assisted natural regeneration. The methodology adopted for this study consisted of inventories of woody species and regenerations in crop fields by placing plots of 50m x 50m during the crop season. Thus twenty (20) plots were placed in the agrosystems according to homogeneity following an equidistance of 300m. The floristic survey made it possible to identify 19 species divided into 9 families of which the most represented are the Fabaceae (72%). The most represented species are P. reticulatum (30%), F. albida (17%) and P. africana (14%). These species also have the highest IVI values. The distribution of individuals by diameter class shows an "inverted J" shape with the shape parameter c = 1.959 (1 <C <3.6), characteristic of populations with a predominance of young or small diameter individuals. The total regeneration density is 2648 stems / ha, grouped into eleven (11) species showing good regeneration and dominated by G. senegalensis representing 61.93% of the density of the inventoried species followed by P. reticulatum (14 , 80%). ANR is a practice that contributes to improving the woody biodiversity of the fields where it is practiced. It is not only an alternative to greening the environment, but also provides several products and services to populations.

Effects of site and tree size on wood density and bark properties of Lebombo ironwood (Androstachys johnsonii Prain)

Background: Wood and bark are important renewable natural resources. Density is an important property that is used to describe wood and bark quality for a number of end uses. However, wood and bark density, bark proportion and dimensions vary with age and site, as well as among and within trees. The aim of this study was to investigate the effect of site, diameter class, and vertical position within the stem on the density of wood and bark, bark volume, bark dry-mass and thickness of Lebombo ironwood (Androstachys johnsonii Prain). Methods: The study was conducted on 93 Lemombo ironwood trees growing in Mozambique. Eight discs were sampled from each selected tree and diameter over and under bark was measured. Bark thickness, bark mass and bark density were determined along with the basic wood density of each disc. Results: The overall average whole-stem properties were estimated at: 786 kg m–3 wood density, 586 kg m–3 bark density, 19% bark volume, 19% bark dry-mass, and 9 mm bark thickness. Height level uniquely explained most of the variation in bark mass (97%), bark volume (95%) and wood density (86%). Diameter class explained most of the variation in bark density (51%) and bark thickness (51%). Site only explained a small proportion of the variation in all dependent variables. Conclusions: Overall, the patterns of variation of all wood and bark properties were highly dependent on tree diameter class and vertical position within the stem. Site differences were not a significant source of variation in the properties studied. Improved knowledge of the wood and bark properties of this species will aid its sustainable management and utilisation.

Comperative study of aboveground biomass and carbon storage between Tembawang and conventional rubber agroforestry in West Kalimantan Indonesia

<p>In the era of intensive oil palm and rubber plantations in Kalimantan, some local communities of Dayak's tribe in West Kalimantan preserved the traditional agroforestry system "Tembawang". In the last two decades, rubber has been planted traditionally by local communities since the expansion of rubber industries. This study aimed to compare tree above ground biomass (AGB) distribution and carbon storage in different DBH (diameter at breast height) classes between Tembawang and conventional rubber plantation in West Kalimantan, Indonesia. Vegetation transect analysis was carried out on two types of traditional agroforestry namely Tembawang and conventional rubber. AGB estimation was based on the existing allometric, carbon storage was estimated from the percentage of biomass. Total AGB of Tembawang was higher than conventional rubber plantation and significantly different (<em>p</em> &lt; 0.01). The highest AGB accumulation both Tembawang and conventional rubber was found at above 50 cm diameter class. The aboveground carbon storage from Tembawang and conventional rubber plantation were 90.26 and 42.01 Mg C ha^-1, respectively. The highest contribution to carbon storage was found at above 50 cm diameter class, estimated 62.58 % from Tembawang and 49.24 % from conventional rubber. AGB and carbon storage at traditional agroforestry in West Kalimantan were greater than varied different agroforestry system, also the estimated value was closed to tropical secondary forests. Tembawang agroforestry has good potential contribution to carbon storage and conservation of native fruit trees of Kalimantan.</p>