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"Natural mortality of trees is extremely variable due to the uncertainty and complexity of the functioning of forest ecosystems. The objective of this study was to develop a stand-level mortality model for Acacia mangium species by relating mortality to stand variables that affect the natural mortality process. 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."

"Papua has been experiencing heavy logging activity in its forests for decades . However, only several studies focused on the effect of logging in the forest ecosystem. This research was aimed to analyze recovery processes of the forest ecosystem. The research was conducted in the logged tropical rainforest in South Papua using ecological approach which used tree communities as biotic and soil condition as abiotic indicators. Data were collected in the logging area of PT Tunas Timber Lestari located in the tropical rainforest of South Papua. There were five groups of forests used in this research i.e. unlogged, one year post selectively-logged, five years post selectively-logged, ten years post selectively-logged and fifteen years post selectively-logged forests. Thirty nested plots were laid on each forest group. Canonical Correspondence Analysis (CCA) was applied to analyze the understory and upperstory plant communities. Understory and upperstory plant communities formed different patterns due to logging. Plant communities in the ten and fifteen years post-selectively logged forests were not similar to those in the unlogged forest. Soil organic matter (SOM) content in the selectively logged forests was lower than that in the unlogged forest. These occurrences indicated that the selectively logged forests were still recovering and required more than fifteen years to be fully recovered."

"Peningkatan emisi gas karbon dioksida mendorong terjadinya pemanasan global dan perubahan iklim. Tanah memiliki kemampuan menyimpan emisi gas karbon dioksida yang diserap oleh vegetasi. Kajian mengenai dinamika fluks emisi gas karbon dioksida tanah dengan perbedaan persentase tutupan kanopi vegetasi di ekosistem Hutan Kota Srengseng belum pernah dilakukan. Penelitian ini bertujuan untuk menganalisis dan membandingkan dinamika fluks emisi gas karbon dioksida tanah di ekosistem Hutan Kota Srengseng dengan perbedaan persentase tutupan kanopi vegetasi serta menganalisis hubungan antara suhu udara, kelembapan tanah, suhu tanah, dan derajat keasaman (pH) tanah dengan fluktuasi emisi gas karbon dioksdia tanah. Metode penelitian yang digunakan adalah metode penangkapan gas rumah kaca menggunakan chamber, pengukuran faktor lingkungan, dan analisis data menggunakan uji ANOVA dan korelasi Spearman. Hasil penelitian serta kesimpulan peneleitian menyatakan bahwa nilai fluks emisi gas karbon dioksida tanah tidak berbeda signifikan di berbagai tutupan kanopi vegetasi Hutan Kota Srengseng. Lebih lanjut, faktor lingkungan yang memiliki hubungan terhadap fluks emisi gas karbon dioksida di Hutan Kota Srengseng, yakni suhu tanah, kelembapan tanah, dan derajat keasaman (pH) tanah, kecuali suhu udara.

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Increasing carbon dioxide gas emissions encourages global warming and climate change. Soil can store carbon dioxide gas emissions, which are absorbed by vegetation. Studies on the dynamics of soil carbon dioxide gas emission fluxes with differences in the percentage of vegetation canopy cover in Srengseng Urban Forest ecosystem have never been carried out. This research aims to analyze and compare the dynamics of soil carbon dioxide gas emission fluxes in Srengseng Urban Forest ecosystem with different percentages of vegetation canopy cover and analyze the relationship between air temperature, soil moisture, soil temperature and soil acidity (pH) with carbon gas emission fluxes soil dioxide. The research method used is the greenhouse gas capture method, which uses a chamber to measure environmental factors and data analysis using the ANOVA test and Spearman correlation. The research results and research conclusions state that no significant difference between the percentage of vegetation canopy cover of the Srengseng Urban Forest and the flux of carbon dioxide gas emissions. Environmental factors related to the flux of carbon dioxide gas emissions in Srengseng Urban Forest are soil temperature, humidity, and acidity (pH), except air temperature.

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"Heart rot on acacia mangium willd. forest stand is critical espicially for mechanical or construction wood based purposes. Failure on understanding the nature and the way it get estabilished into the tree stem may cause high economic consequences...."

"Kandungan ion logam Timbal dalam air cenderung sangat rendah sehingga proses analisisnya memerlukan teknik prakonsentrasi menggunakan resin penukar ion. Penggunaan resin penukar ion dalam teknik prakonsentrasi memiliki kelebihan, diantaranya faktor kehilangan analit dapat diminimalkan dan jumlah resin yang digunakan sedikit dan ramah lingkungan. Pada penelitian ini, ekstrak tanin daun Akasia Mangium digunakan sebagai bahan baku pembuatan resin penukar ion. Reaksi polimerisasi ekstrak tanin dengan penambahan H2SO4 pekat dilakukan agar resin tidak mudah larut dalam air. Hasil polimerisasi ekstrak tanin PET dikarakterisasi secara kualitatif menggunakan spektroskopi Fourier Transform Infra Red FTIR dan kuantitatif dengan pengukuran Total Karbon Organik TOC . Untuk mengetahui kemampuannya sebagai resin penukar ion, PET diuji dengan parameter adsorpsi, pola isoterm adsorpsi, dan validasi metode analisis. Kapasitas adsorpsi optimum resin PET diperoleh sebesar 5,261 mg/g pada pH 7 dan waktu kontak 120 menit, sedangkan parameter retensi optimum diperoleh pada konsentrasi eluen HNO3 2 M dengan volume 5 mL. Isoterm adsorpsi yang sesuai untuk resin PET mengikuti isoterm Freundlich dengan nilai regresi 0,9919. Berdasarkan uji validasi metode analisis diperoleh nilai kebolehulangan dengan RSD sebesar 0,97 , linearitas R2 0,9986 pada rentang 0,25-100 ppm, sensitivitas sebesar 0,067 ppm, batas deteksi Limit of Detection/LOD sebesar 0,019 ppm dan recovery sebesar 102,3 -110,91 . Hasil uji sampel menunjukan kadar Timbal di sungai Ciliwung sebesar 105-267 ppb.

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The heavy metal ions contained in water tend to be so low that the analysis process requires preconcentration techniques using ion exchange resins. The use of ion exchange resins in preconcentration techniques has advantages, such as factors for loss of analyte can be minimized and the amount of resin used is small and environmentally friendly. In this study, Acacia Mangium leaf tannin extract was used as the raw material for ion exchange resin production. The polymerization reaction of tannin extract with the addition of concentrated H2SO4 is done so that the resin is not easily soluble in water. Results from polymerization of tannin extract PET were characterized qualitatively using Fourier Transform Infra Red FTIR and quantitative spectroscopy with Total Organic Carbon TOC measurements. To find out its ability as ion exchange resin, PET was tested with adsorption parameters, adsorption isotherm patterns, and validation of analytical methods. The optimum adsorption capacity of PET resin was obtained at 5,261 mg g at pH 7 and contact time of 120 min, while the optimum retention parameter was obtained at eluent concentration of HNO3 2 M in 5 mL of volume. The adsorption isotherms suitable for PET resins that follow Freundlich isotherms with a regression value of 0.9919. Based on the validation test of the analysis method, the value of repeatability with RSD is 0.97 , the linearity of R2 0.9986 in the range of 0.25 100 ppm, the sensitivity of 0.067 ppm, the limit of detection Limit of Detection LOD of 0.019 ppm and the recovery of 102.3 110.91 . The result of the sample test shows that the Lead level in Ciliwung River is 105 267 ppb."

"Rainfall interception losses were monitored for six months and related to vegetation and rainfall characteristics at the BPK-ODA research site in the upper stream of Mentaya river, Central Kalimantan. The rainfall interception losses were quantified based in the records of 52 selected rainfall events within the range of 8.5-135.5 mm. Over 6 months in one hectare pristine tropical rainforest, 217 mm (11%) of 1990 mm gross rainfall occurring in the research was loss to the atmosphere. Canopy through fall equaled 1745 mm (87.7%) of gross rainfall whereas stem flow represented 28 mm (1.3%). These findings are comparable to interception studies carried out in Sabah and Amazonian rainforest."

"Penelitian ini mengembangkan sistem pencahayaan alami atas karena keterbatasan akses cahaya pada ruang hunian di kawasan padat penduduk. Fokus penelitian ini adalah penggunaan light pipe dua aperture untuk meningkatan kenyamanan pengguna secara visual dan kondisi termal di kawasan padat penduduk. Penelitian terdahulu menyatakan bahwa sistem pencahayaan alami atas, light pipe standar dapat membawa cahaya masuk pada deep-plan building dimana distribusi dan tingkat pencahayaan dipengaruhi oleh spesifikasi dan material light pipe juga ketinggian ruang. Penggunaan light pipe dua aperture disesuaikan dengan karakteristik ruang padat digunakan untuk membawa dan mendistribusikan cahaya masuk kedalam ruang. Maka pada penelitian inispesifikasi light pipe meliputi jenis glazing kolektor, diameter, panjang pipa, dan ketinggian ruang hunian ditetapkan pada simulasi dan eksperimen model. Ada dua belas konfigurasi ruang hunian dengan luas hunian 5 meter persegi, 7,5 meter persegi dan 10 meter persegi dan material ruang yang berbeda seperti kayu dan semen. Ruang hunian dan material ruang diuji melalui simulasi dan eksperimen model skala. Hasil simulasi dan eksperimen menunjukkan ada pengingkatan tingkat iluminasi sebesar 8,4%-14,8%, distribusi iluminasi sebesar 1,05%-31,36% dan kondisi termal seperti RH mengalami peningkatan 6,14 %-10,92% begitu pula dengan temperatur meningkat sebesar 2.5%-10.57%.

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This study aims to develop a special daylight system due to limited access to daylight in residential spaces in densely populated kampung. This research focuses on using a two-aperture light pipe to improve user comfort visually and thermal conditions in densely populated kampung. Previous research has shown that the top daylighting system, the standard light pipe, can bring daylight into the deep-plan building where the distribution and level of lighting influence the specifications and material of the light pipe and the height of the room. A two-aperture light pipe adapted to a dense kampung's characteristics to carry and distribute daylight into the room. Thus in this study, the light pipe specifications include the type of glazing collector, diameter, pipe length, and the height of the residential space was control in simulation and experiment. There were twelve residential room configurations with 5 square meters, 7.5 square meters, and 10 square meters and different space materials such as wood and cement. Residential space and space materials tested through simulations and scale model experiments. Simulation and experimental results show an increase level illumination by 8.4%-14.8%, the distribution of daylight by 1.05%-31.36%, and thermal conditions such as RH an increase of 6,14%-10.92% as well with temperature increased by 2.5%-10.57%."

"ABSTRAKPembinaan ekosistem hutan dilakukan antara lain melalui kegiatan pembangunan hutan tanaman di wilayah-wilayah kritis dan lahan kosong. Dengan membangun hutan tanaman pada lahan-lahan kritis diharapkan akan memberi dampak positip, baik terhadap makhluk hidup yang ada di dalam hutan maupun masyarakat di sekitarnya.Pembangunan hutan tanaman dilakukan antara lain dengan cara tanam banjarharian dan cara tanam tumpangsari dengan penanaman jenis-jenis pohon yang cepat tumbuh. Kegiatan pembangunan hutan tanaman cukup penting dibicarakan karena menyangkut banyak aspek, baik aspek ekologi, maupun aspek sosial ekonomi. Penelitian ini bertujuan untuk melihat pembentukan vegetasi hutan tanaman melalui penerapan cara tanam banjarharian dan cara tanam tumpangsari. Penelitian memakai rancangan percobaan faktorial. Perlakuan adalah semua kemungkinan kombinasi taraf dari beberapa faktor, yakni jenis akasia dalam cara tanam banjarharian, jenis akasia dalam cara tanam tumpangsari, jenis albisia dalam cara tanam banjarharian dan jenis albisia dalam cara tanam tumpangsari. Analisis data melalui analisis keragaman, analisis uji jarak berganda Duncan, analisis tabel kontingensi disertai analisis deskriptif. Hasil penelitian menunjukkan vegetasi hutan dalam cara tanam tumpangsari tumbuh lebih cepat daripada dalam cara tanam banjarharian. Jenis akasia tumbuh lebih cepat dibanding albisia. Penutupan tajuk tanaman dalam cara tanam tumpangsari lebih luas daripada dalam cara tanam banjarharian. Kerapatan tegakan menunjukkan kecenderungan menyusutnya jumlah batang perhektar pertahun sekitar 116 batang baik dalam cara tanam banjarharian maupun dalam cara tanam tumpangsari. Keanekaragaman jenis tumbuhan bawah dan permudaan menunjukkan dalam cara tanam banjarharian jenis tanaman lebih beraneka dibanding dalam cara tanam tumpangsari. Kerapatan tumbuhan bawah dan permudaan menunjukkan tidak terdapat kerapatan individu yang menyolok antar kedua cara tanam. Jenis-jenis yang tumbuh dalam hal ini menunjukkan jenis-jenis yang mampu beradaptasi dengan lingkungan setempat. Jenis albisia terlihat tumbuh tertekan di lingkungan setempat dibanding jenis akasia. Untuk menghindari hutan rnonokultur melalui hanya menanami akasia yang sudah terlihat tumbuh baik, perlu mencari substitusi jenis albisia untuk pencampuran jenis dalam tegakan hutan. Jenis puspa yang gampang tumbuh di lingkungan setempat perlu dipertimbangkan dalam hal ini. Pemupukan yang dilakukan harus diupayakan secara baik terutama saat-saat awal penanaman di lapangan.Tumbuhan bawah dan permudaan yang didominasi oleh jenis-jenis pionir pada dasarnya meriipakan elemen penunjang terhadap fungsi hutan. Oleh karenanya tumbuhan bawah dan permudaan ini tidak perlu dibabat habis karena keberadaannya menyangkut peran fungsi hutan. Tumpangsari sangat berperan terhadap keberhasilan tanaman hutan, di samping itu akan pula memberi manfaat terhadap kondisi sosial ekonomi masyarakat setempat. Dampak kegiatan tumpangsari terhadap masyarakat sekitar sementara ini belum terlihat nyata, karena pemanfaatan tenaga kerja masih mengambil dari daerah di luar kawasan hutan. Pemanfaatan produk kayu di wilayah ini boleh disebut belum optimal karena masih hanya memperuntukkan hasil kayu sebagai bahan baku pulp saja. Pengembangan pemanfaatan produk kayu perlu dievaluasi, karena hendaknya pembangunan hutan mencakup peran ekologis maupun ekonomis.

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ABSTRACT

Forest ecosystems development has been done other through the plantation forest establishment in arid area and land bare. It is hope the plantation forest establishment gives positive impacts to the living organisms in the forest and the surroundings community.

Plantation forest establishment has been done by the daily wage system (banjarharian system) and the taungya system (tumpangsari system) with fast growing species. This activity is necessary to be considered dealing with many aspects, ecological aspects or social economical aspects.

This research aims to see vegetation growing of plantation forest through implementing daily wage system and taungya system. This research used factorial experimental design. The treatment was possibility of level combination from amount factor, acacia in daily wage system; acacia in taungya system; albisia in daily wage system and albisia in taungya system. Data analyzed by variance analysis, Duncan multiple range tests, contingency table completed by descriptive analysis.

The result of the research indicated that the vegetation growing of plantation forest in taungya system was more rapidly than in daily wage system. The acacia grew faster than albisia. Forest canopy grew wider in taungya system than in daily wage system. Stand density decreased about 116 stems per year in both systems.

The diversity ground flora (ground cover and regeneration plants) indicated that in daily wage system was more diverse than in taungya system. The density of ground flora indicated that in both system didn't show difference density. The species of ground flora that grown, indicated that they were the species of adaptable to the environment.

The albizia growing was less suitable with the site condition compared with the acacia. It's needed more concern by the management to reevaluate this option of species. By supporting the combination species, to avoid monoculture forest it's necessary to consider puspa species that the species with the suitable ones. Fertilizing which done to avoid the loosing of nutrient should keep on undertaking.

The ground flora was dominated by pioneer species, basically as the supporting element to forest function. Therefore the ground flora shouldn't clear-cut because their existence has big role in forest function.

Taungya system has positive impact to succeed plant growing, beside that the system will give advantages to people surrounding the plantation forest. This condition has not been obviously shown because the manpower for this activity was recruited from other area.

The utilization of main products of plantation forest in this area was not considered optimal since they were still for pulp and popper row material only. Therefore the development in utilizing the wood, products is need to be considered as well as efficiency, because the forest. Establishment should including ecological aspects and economical aspects."