The Dynamics of Species Composition Stand Structure and Above Ground Biomass of Undisturbed Forest in East Kalimantan

Dinamika Komposisi Spesies Struktur Pohon dan Biomasa di Hutan Terganggu di Kalimantan Timur. Kajian dinamika komposisi spesies dan biomasanya dilakukan selama 4,3 tahun (Desember 2004 - April 2009) di hutan terganggu Kalimantan Timur. Untuk melakukan kajian di gunakan 6 plot permanen (100x100 m2), yang berada di hutan penelitian Samboja. Semua pohon berdiameter > 10 cm dbh (diukur pada posisi 1,3 m diatas tanah). Pada Desember 2004,tercatat 2143 pohon tersebar di plot tersebut terdiri dari 39 famili, 82 genus dan 111 spesies. Pada pengamatan April 2009 tercatat 2466 pohon terdiri dari 40 famili, 86 genus dan 123 jenis.Sebagian besar spesies yang mendominasi adalah Garcinia nervosa dan Trigonostemon laevigatus tetapi setelah pengamatan pada tahun 2009, keduanya tidak lagi mendominasi. Selama kurun 4,3 tahun terjadi penambahan kepadatan 15,1%, basal area 12,9% dan biomasa 11,6%. Penambahan kepadatan tercatat meningkat dari 357 menjadi 411 pohon/ha. Basal area meningkat mulai dari 20,09 menjadi 22,67 m2 ha-1, sedangkan biomasa meningkat dari 286,3 menjadi 319,4 ton ha-1

Changes in the Species Composition, Stand Structure and Aboveground Biomass of a Lowland Dipterocarp Forest in Samboja, East Kalimantan

The dynamics of species composition, stand structure and aboveground biomass were studied over a 4.3-yr period (December 2004 – April 2009) in a lowland dipterocarp forest of Samboja, East Kalimantan. This study was conducted in six permanent sample plots (100 m x 100 m each) distributed over an area of 26.5 ha of Samboja Research Forest. All woody plants = 10 cm dbh (diameter at 1.3 m aboveground) were identified. In December 2004, 2.143 trees were measured in the six plots, consisting of 39 families, 82 genera and 111 species. The condition in April 2009 (after 4.3 yr) was: 2,466 trees, 40 families, 86 genera and 123 species. Most species were found in both occasions. Fourteen new species were registered, which contributed to 9.8% of a net addition of the total number of species found in the six plots. Over the 4.3-yr period, there was also an increase of 15.1% in density, 12.9% in basal area, and 11.6% in aboveground biomass, respectively. The density increased from 357 to 411 trees per ha; the basal area increased from 20.09 to 22.67 m2 ha-1; and the aboveground biomass increased from 286.3 to 319.4 ton ha. The family Dipterocarpaceae was the richest in species (more than 20 species found in both occasions), followed by Euphorbiaceae, Burseraceae, Fabaceae, and Anacardiaceae (more than five species). Most genera (80%) contained just one species, but Shorea with 13 species was the richest. Four families (Dipterocarpaceae, Fabaceae, Myrtaceae and Lauraceae) contained more than 80% of the aboveground biomass in both occasions (75% of them from Dipterocarpaceae family). The increases in species richness and density did not cause any significant differences in the diversity index and diameter distribution. This condition suggested that forest vegetation of the study site maintains its diversity composition and structural features over the period of study

Generalized Height-diameter Models for Acacia Mangium Willd. Plantations in South Sumatra

The aim of this study was to develop a generalized height-diameter model for predicting tree height of Acacia mangium plantations in South Sumatra that could account for the variability of site and stand conditions. Six commonly used non-linear growth functions (i.e. Gompertz, Chapman-Richards, Lundqvist-Korf, Weibull, modified logistic, and exponential) were selected as candidate base models and were fitted to individual tree's height-diameter data of A.mangium plantations. A total of 13,302 trees collected from permanent sample plots with various spacing , stand age, and site quality were available for this study. The data were split into two sets: one set being the majority (75%) was used to estimate model parameters and the remaining data set (25%) was used to validate the models. The results showed that the six base models produced almost identical fits with a relatively high root mean squared error (± 3.4 m) and a relatively low proportion of the total variation in obser ved tree height (52.5 - 53.4%). The Lundqvist-Korf (LK) model performed slightly better than the other models based on the goodness of fit as well as bias and standard errors of the predictions. This LK model can be fitted easily and provided more satisfactory fit when additional variables were included into the model, hence was selected as the base model. Introducing stand variables into the selected base model resulted in a significant improvement of the accuracy for predicting heights. The root mean squared error decreased by the value between 0.5564 and 1.4252 m and the proportion of variation explained by the model increased by the value between 13.88 and 33.21%. The best improvement based on fit and model validation was achieved by the generalized height-diameter model with inclusion of stand age and site index

Modelling Natural Mortality of Tropical Plantation Species Acacia Mangium Willd.

Natural mortality of trees is extremely variable due to the uncertainty and complexity of the functioning of forest ecosystems. To overcome this uncertainty, a two-step mortality model was applied for unthinned stands of Acacia mangium species. The model was developed using data from l97 permanent sample plots measured periodically at 1-yr time intervals from 2-4 years until 8-11 years after planting in South Sumatra, Indonesia. The model consists of two complementary equations. The first equation is a logistic function predicting the probability of mortality incidence depending on stand density, site index and stand age. The second equation estimates the reduction in the number of surviving stems observed in a stand where natural mortality occurs. Nine equations were fitted using data from permanent sample plots where trees died over the time period and the best model was selected. Estimates from this second model were then adjusted by a factor equal to the probability of mortality applying three different approaches: probabilistic two-step, deterministic threshold and stochastic. All methods revealed no significant difference between the observed and the predicted number of surviving stems per ha. The probabilistic two-step approach, however, produced more consistent and the most accurate estimates. This method should provide reliable prediction when it is to be used in forest productivity prediction and management system for the species

Kajian Sosial Ekonomi Masyarakat Sekitar Sebagai Dasar Penetapan Tipe Penyangga Taman Nasional Gunung Merbabu, Jawa Tengah

Zona penyangga seringkali ditawarkan sebagai solusi konflik kepentingan konservasi keanekaragaman hayati di kawasan konservasi dengan kepentingan manusia di sekitarnya. Taman Nasional Gunung Merbabu merupakan salah satu taman nasional di Pulau Jawa yang mengalami tekanan dari penduduk di sekitarnya. Salah satu solusi yang akan diaplikasikan adalah pembuatan penyangga taman nasional. Penelitian ini bertujuan mengidentifikasi potensi biofisik Taman Nasional Merbabu, sosial-ekonomi, dan aspirasi masyarakat sekitarnya serta kebijakan pemerintah daerah dan pengelola taman nasional sebagai dasar memformulasikan tipe penyangga yang tepat. Wawancara terstruktur dengan responden dan focus group discussion dilakukan untuk mengumpulkan data primer dan memformulasikan tipe penyangga. Hasil penelitian ini merekomendasikan lima tipe penyangga Taman Nasional Gunung Merbabu, yaitu: (1) Pembuatan zona penyangga di tanah milik, di sekitar TN Gunung Merbabu; (2) Pemanfaatan kawasan secara terbatas melalui mekanisme Pengelolaan Hutan Bersama Masyarakat; (3) Pemanfaatan tradisional hasil hutan bukan kayu; (4) Pemanfaatan jasa lingkungan berupa air dan wisata alam; (5) Penyangga ekonomi tidak berbasis lahan

The Forest Observation System, building a global reference dataset for remote sensing of forest biomass

Forest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (AGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. AGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world's forests. All plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS- based biomass products while developing new synergies between the RS and ground-based ecosystem research communities.</p