Selling system of sengon (Paraserianthes falcataria) timber in community forests without using appropriate tree L. volume models may generate profit loss for the farmers. The objectives of this study were to develop volume models of sengon and to evaluate the profit losses of commonly practiced techniques for selling the sengon timber in community forest. The result showed that the proposed volume model can be used accurately to estimate the volume of sengon trees in the community forest by measuring tree diameters. This study confirmed that the selling system based on per log and total stand area caused profit losses of 24.99% and 32.19% respectively, to the farmers. To avoid such disadvantages, therefore the use of the proposed volume model is recommended to facilitate accurate estimation of the volume of sengon trees.

Kabesak (Acacia leucophloea) is a particular plant species and recognized to have important benefits to the local people of Timor Island. The people of Timor Island use kabesak leaves as animal feed in the dry season and kabesak wood is used as building materials and furniture. The purpose of this study was to determine the stand and site characteristics of kabesak in the western region of Timor, Indonesia. The means of density, frequency, dominance, and importance value index were analyzed. The results showed kabesak stand structure in secondary forest land, grassland, and shrubs, as well as garden showed the J-inverted shaped, which implies that natural regeneration was a proper continuation. Kabesak had significant associations with a few plants' species, both negative and positive types. The result of regression analysis of the principal components showed that the contribution of edaphic factor influences the population density of kabesak. Silt fraction and phosphorus content were found to have the highest positive effect on the density, while sand fraction and sodium content were found to have the highest negative effects of kabesak. A test for altitude with Tukey test (α = 0.05) reveals that kabesak from 0-300 m a.s.l., 300-600 m. asl., 600-900 m a.s.l. were not different from each other, while altitude >900 m a.s.l. was significantly different from the other groups. ABSTRAKKabesak (Acacia leucophloea) adalah spesies tanaman yang dikenal memiliki manfaat penting bagi penduduk lokal Pulau Timor. Masyarakat Pulau Timor memanfaatkan daun kabesak sebagai pakan ternak di musim kemarau dan kayunya dimanfaatkan sebagai bahan bangunan dan meubel. Tujuan dari penelitian ini adalah untuk menentukan karakteristik tegakan dan tempat hidup kabesak di wilayah Timor Barat, Indonesia. Penelitian ini dianalisis dengan menggunakan indeks kepadatan, frekuensi, dominansi, dan indeks nilai penting. Struktur tegakan kabesak di lahan hutan sekunder, padang rumput, dan semak belukar, serta taman menunjukkan bentuk J terbalik, yang menyiratkan bahwa regenerasi pada tiga jenis lahan berjalan baik. Kabesak memiliki hubungan yang signifikan dengan beberapa spesies tanaman, baik tipe negatif maupun positif. Hasil analisis regresi komponen utama menunjukkan bahwa kontribusi faktor tanah mempengaruhi kepadatan populasi kabesak (individu ha -1 ). Variabel tanah yang memiliki efek positif tertinggi terhadap kepadatan kabesak adalah fraksi debu tanah dan fosfor (P), sedangkan yang memiliki efek negatif tertinggi adalah tanah berpasir dan fraksi natrium. Tes ketinggian dengan uji Tukey (α = 0,05) mengungkapkan bahwa 0-300 m dpl., 300-600 m dpl., 600-900 m dpl tidak berbeda satu sama lain, sementara ketinggian> 900 m dpl secara signifikan berbeda dari kelompok lain.

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Form factors and volume models are often be used in the estimation of tree volumes. However, a few studies have developed and evaluated the accuracy of form factors and volume models for estimating tree volumes of community forests. This study aimed to formulate form factors and volume models and assess their prediction accuracy for estimating tree bole volumes of mahogany at community forests in Central Java. This study used 120 sample trees with diameters of 6–38 cm to formulate artificial and absolute form factors and to develop tree bole volume models. These form factors coupled with bole height and total height were used in simple volume equations. Regression analyses were used to develop volume models using the diameter and total height as predictors. The simple volume equations and volume models' prediction accuracy was evaluated using a cross-validation dataset and independent dataset (30 sample trees). The artificial form factor (0.68 ± 0.11) of mahogany, which was higher than the absolute form factor (0.46 ± 0.09), provided accurate estimates of tree bole volumes when it was used with the bole height instead of the total height. The volume model that uses diameter and total height produced the most accurate estimates, while the volume model that uses diameter alone provided the most practical yet reliable tool for estimating tree bole volumes of mahogany. The results of this study are useful for improving community forest management.

Untuk mewujudkan kelestarian hasil tegakan merbau diperlukan metode pengaturan hasil yang tepat. Namun sampai saat ini, pemerintah masih menggunakan metode pengaturan hasil yang bersifat umum untuk seluruh jenis tegakan, sehingga tidak cocok untuk tegakan merbau yang riapnya rendah dan populasinya jarang. Alternatifnya, pengaturan hasil tegakan merbau dapat menggunakan metode pengaturan hasil berbasis dinamika struktur tegakan. Metode tersebut dapat membantu pengelola hutan untuk menentukan jatah tebang tahunan dan merumuskan berbagai skenario pengaturan hasil sesuai dengan tujuan pengelolaan dan karakteristik tegakan merbau yang dikelolanya. Dalam implementasinya, metode tersebut dapat mendorong pengelola hutan untuk memperbaiki praktik-praktik pengelolaan hutannya menjadi lebih baik.