Pertumbuhan dan Sintasan Juvenil Teripang Pasir Holothuria scabra pada Pemeliharaan Dengan dan Tanpa Rumput Laut Gracilaria sp., Menggunakan Keramba Apung dan Tancap di Tambak

<p><strong>Growth and Survival of Sandfish <span style="text-decoration: underline;">Holothuriascabra</span> Juveniles </strong><strong>Grown </strong><strong>with and without Seaweed <span style="text-decoration: underline;">Gracilaria</span> sp</strong><strong>.,</strong><strong> using Floating and Fixed Hapas in </strong><strong>Earthen </strong><strong>Pond</strong><strong>. </strong><span style="text-decoration: underline;">Holothuriascabra</span> known as sandfish have long been used for pharmaceutical, cosmetic, and food industries.Juveniles production is one of the ways to address the problem of raw material availability due to declining sandfish population in the wild. This research aimed to determine growth performance and survival of sandfish juveniles reared with and without seaweed <span style="text-decoration: underline;">Gracilaria</span> sp. using floating and fixed hapas in earthen pond. The research was conducted from May to September 2014. A completely randomized design was used to arrange 12 hapas of four treatments groups with three replicates including floating hapas without <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp. (ATR), floating hapas with <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span>sp. (ADR), fixed hapas without <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp. (TTR) and fixed hapas with <span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp. (TDR). Some parameters was observed includingweight increment, Growth Rate (GR),Specific Growth Rate(SGR), Biomass, Survival, and Water Quality. The result showed that GR and SGR were not significantlydifferent among treatments (P&gt;0.05). Survial and Biomass showed significant difference among treatments (P &lt;0.05). ATR has the highest GR, SGR, survival, dan biomass whereas TDR has the lowest GR, SGR, survival, dan biomass. Water quality parameters were in optimal range for sandfish rearing. Added<span style="text-decoration: underline;">G</span><span style="text-decoration: underline;">racilaria</span> sp.tend to inhibitGR, SGR, survival, dan biomass.<strong></strong></p>

Pertumbuhan Riap Diameter Pohon Bakau Kurap (Rhizophora Mucronata) Di Lampung Mangrove Center

Bakau kurap (R. mucronata) is a true mangrove. The height of this mangrove could reach 27 m and rarely exceed 30 m. The diameter trunk of this mangrove could reach 70 cm. R. mucronata stands was found in Lampung Mangrove Center (LMC), it was located in Margasari Village district Labuhan Maringgai, East Lampung Regency. The purposes of this study were to determine the diameter increment, growth models and stand growth past of R. mucronata at LMC. The research was conducted on July to August 2015. The method used measurement of diameter time series for three years (2013, 2014, and 2015) on circle form permanent plots with a radius 7 m of length are divided into three thinning blocks (A, B, and C). Block C was the control block or block that was not thinned and large thinning in blocks A and B, respectively 54.5% and 41.7%. The results indicated that the biggest diameter increment of three block at the age of 22nd years = 0.467 cm year-1. The estimation model of stand diameter (D) and diameter increment (MAI-d) based on the age of stand (X) could be formulated as follows: 1) Blok A D = 8,996 X0,021; MAI-d = 0,451 X0,035, 2) Blok B D = 8,215 X0,124; MAI-d = 0,412 X0,039, 3) Blok C D = 7,159 X0,074; MAI-d = 0,359 X(-0,012). Forecasting growth stands diameter R. mucronata age of 32nd years on the blocks A, B and C in a row were 10,280cm, 9,463cm, and 7,796cm while the diameter increment were 0,467cm, 0,430cm, and 0,354cm. Key words : Diameter increment, forecasting, Lampung Mangrove Center, Rhizophora mucronata

Overcoming data sparseness and parametric constraints in modeling of tree mortality: a new nonparametric Bayesian model

Accurately describing patterns of tree mortality is central to understanding forest dynamics and is important for both management and ecological inference. However, for many tree species, annual survival of most individuals is high, so that mortality is rare and, therefore, difficult to estimate. Furthermore, tree mortality models have potentially complex suites of covariates. Here, we extend traditional and recent approaches to modeling tree mortality and propose a new nonparametric Bayesian method. Our model is constrained to both reflect and distinguish known relationships between mortality and its two key covariates, diameter and diameter increment growth, but it remains sufficiently flexible to capture a wide variety of patterns of mortality across these covariates. Our model also allows incorporation of outside information in the form of priors, so that increased mortality of large trees can always be formally modeled even when data are sparse. We present results for our nonparametric Bayesian mortality model for maple ( Acer spp.), holly ( Ilex spp.), sweet gum ( Liquidambar styraciflua L.), and tulip-poplar ( Liriodendron tulipifera L.) populations from North Carolina, USA.

Boreal mixedwood tree growth on contrasting soils and disturbance types

Mixedwood forests are an ecologically and economically important ecosystem in the boreal forest of northern Canada. The objectives of this study were to (i) compare the age–height relationships for dominant tree species growing on two contrasting soil types and originating from different disturbances (logging versus wildfire), and (ii) determine the influence of competition on tree growth. Eight stands were selected that encompassed two age-classes replicated on two soil types (clay loam and sand) in a split-plot design. Four of the eight stands originated from logging (21–26 years old), and <F"Times">the four others originated from wildfires (80 years old). Nonlinear age–height analyses were used to compare annual height and radial increment growth of black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.). Species, soil type, and size class explained significant amounts of the measured variation in the age–height models. Aspen, black spruce, and jack pine were 16%, 27%, and 19% taller, respectively, on clay soils than on sandy soils at the burned stand. Tree heights did not differ significantly among species or between soil types in logged stands. Diameter growth decreased as competition increased for black spruce and jack pine in the burned stands. The results for these three important boreal tree species are discussed in the context of sustainable forestry for boreal mixedwood forests.

AN ANALYSIS OF GROWTH AND DROUGHT TOLERANCE IN RUBBER DURING THE IMMATURE PHASE IN A DRY SUBHUMID CLIMATE

An experiment with the objective of evaluating the performance of 15 clones of rubber (Hevea brasiliensis) was conducted in the Konkan region of Western India. The clones under evaluation were RRII 5, RRII 6, RRII 105, RRII 208, RRII 308, RRIC 52, RRIC 100, RRIC 102, RRIC 105, RRIM 605, PB 260, PB 310, PB 311, PR 255, and PR 261. The region is a trial environment for the crop and experiences more than seven rainless months and severe drought in the summer months. Data on monthly girth growth w ere collected for six years from a trial with randomized block design. The growth of clones in terms of monthly girth increment growth (GIN, cm month−1) seasonal mean girth increments (MGIN, cm season−1) and mean relative increment rates (MRIR, mm cm−1 season−1) as well as annual MGIN (cm a−1) and MRIR (mm cm−1 a−1) was studied. Correlation analysis was performed to understand the effect of seasonal growth on the final growth. At the beginning of the study, the largest girth noted was for the clone RRII 6 (22. 5 cm) followed by RRII 208 (22.0 cm). PR 261 with a girth of only 14.2 cm was the least vigorous among the clones. A large portion of the growth occurred in the wet season only. During the dry season the growth rates of the clones declined substantially and decreases in girth ranging from 0.2 mm to 0.5 mm were noticed in most of the clones. At the end of the study period the largest girth observed was for clone RRII 208 (49.3 cm) and the lowest for PR 261 (39.3 cm). The highest proportion of tappable trees noted was for clone RRII 208 (52.4%) and the lowest for PR 261 (2.7%). The pooled average of tappable trees was on ly 17.5%. The data revealed that the immaturity period for Hevea in the region will not be less than 9 years under rainfed conditions. From the analysis based on the final girth it was concluded that clones RRII 208, RRIC 52, RRII 6, RRIC 100 and RRIC 102 are more tolerant to drought while RRII 105, RRIC 105, RRII 5, RRIM 605, PB 310, PB 260, PB 311, PR 255, RRII 308 and PR 261 are less tolerant. The results of correlation indicated that by analysing the growth, potentially drought-toleran t clones can be identified.