Jenis Tanah, Komposisi dan Keanekaragaman Jenis Tegakan Pada Pengusahaan Hutan Alam Secara Konvensional dan RIL

Dalam melakukan pengelolaan hutan alam produksi, penggunaan sistem pemanenan yang memberikan dampak kerusakan lingkungan minimal sangat diharapkan. Salah satu sistem pemanenan yang dapat meminimalisir dampak kerusakan lingkungan akibat pemanenan adalah Reduced Impact Logging (RIL). Namun demikian, data hasil kajian terkait dampak sistem pemanenan konvensional dan RIL terhadap komposisi, keanekaragaman jenis dan juga sebaran jenis tanahnya masih sangat sedikit. Padahal, data tersebut sangat penting sebagai bagian strategi untuk implementasi pengelolaan hutan alam lestari dapat lebih berhasil kedepan. Tulisan ini bertujuan menginformasikan sebaran jenis tanah, komposisi dan keanekaragaman jenis tegakan pada wilayah pengusahaan hutan alam yang telah menerapkan sistem pemanenan secara konvensional dan RIL dalam rangka mendukung strategi pengelolaan hutan alam lestari. Plot berbentuk lingkaran digunakan untuk melakukan survei analisis vegetasi di tiga (3) areal IUPHHK-HA yaitu PT. A, PT. B, dan PT. C di Provinsi Kalimantan Tengah serta data yang terkumpul selanjutnya dianalisis lebih lanjut yaitu INP (Indeks Nilai Penting), indeks keanekaragaman jenis (Shannon-Wiener), indeks kekayaaan jenis (Margalef) dan indeks kemerataan jenis. Hasil penelitian di seluruh lokasi studi menunjukkan sebaran jenis tanah yang didominasi oleh kompleks Kambisol-Podsol sebesar masing-masing 82,0% (PT. A), 45,38% (PT. B), 48,48% (PT. C) yang memiliki tingkat kesuburan rendah dan ketersediaan hara yang rendah; tidak ditemukan banyak perubahan keberadaan famili-famili tumbuhan berdasarkan 5 spesies dengan INP tertinggi pada masing-masing tingkat pertumbuhan pancang, tiang dan pohon (selisih rata-rata nilai INP pada semua tingkatan pertumbuhan berada dibawah nilai 10%) dimana masih sangat didominasi oleh famili-famili Dipterocarpaceae, Myrtaceae, Fabaceae dan Fagaceae; tidak ditemukan banyak perubahan terhadap nilai keanekaragaman (nilai 3,00-3,19), kekayaan (nilai 6,57-7,61) dan kemerataan jenis (nilai 0,82-0,88). Dengan demikian, sistem pemanenan pada hutan alam yang dilaksanakan dengan baik yang mempunyai dampak terhadap lingkungan minimal akan memberikan keberlanjutan komposisi tegakan dan keanekaragaman hayati untuk mendukung terjaminnya kelestarian hutan pada areal pengusahaan hutan alam produksi di Indonesia.ABSTRACTIn managing natural production forest, the use of a logging system that provides minimal damage is highly desirable. One of the logging systems that can minimize the impact of damage due to logging is Reduced Impact Logging (RIL). However, data from studies related to the impact of conventional and RIL logging systems on the composition, species diversity and distribution of soil types are still very few. In fact, the data is very important as part of a strategy for implementing sustainable natural forest management to be more successful in the future. This paper aims to inform the distribution of soil types, composition and species diversity of stands in forest concession areas that have applied conventional logging systems and RIL in order to support sustainable natural forest management strategies. The circular plot was used to conduct a vegetation analysis survey in three (3) IUPHHK-HA areas, namely PT. A, PT. B, and PT. C in Central Kalimantan Province and the data collected were then analyzed further, namely the INP (Importance Value Index), the species diversity index (Shannon-Wiener), the species richness index (Margalef) and the species evenness index. The results of the research in all study locations showed that the distribution of soil types was dominated by the Kambisol-Podsol complex as amounted 82,0% (PT. A), 45,38% (PT. B), 48,48% (PT. C) which had low fertility and low nutrient availability; not found much change in the existence of plant families based on 5 species with the highest INP at each growth stage of saplings, poles and trees (difference in the average INP values at all growth stages below 10%) that still very much dominated by the Dipterocarpaceae, Myrtaceae, Fabaceae and Fagaceae families; not found much change in the value of diversity (value 3,00-3,19), richness (value 6,57-7,61) and evenness of species (value 0,82-0,88).Thus, a logging system that is carried out properly in managing natural forest that has minimum environmental impact will provide sustainability of stand composition and biodiversity to support the assurance of forest sustainability in natural forest concession areas in Indonesia..

Opportunity cost of natural forest management in the Arenal-Huetar Norte Conservation Area, Costa Rica

Background: Part of the success of forest conservation programs is due to the economic sustainability they can provide to owners of forest resources, and how these management mechanisms can be used within an increasingly aggressive productive landscape matrix. However, there are currently no precise or up-to-date data on the economic relationships between land uses and their respective productive activities. This study designed a model to evaluate the opportunity cost of natural forest management, taking as a reference the primary productive activities that take place within the Arenal-Huetar Norte Conservation Area, in Costa Rica. Methods: Profitability data from 24 sites in natural forests with a forest management plan approved by the State Forest Administration was used, as well as geographic and productive information on alternative land uses. Results: Based on these data, an opportunity cost map was generated which shows a marked segregation of the forests into two main areas: a) a high-opportunity cost area, located south of the study area; and b) a medium-low opportunity cost area, to the center-north of the study area. Conclusions: It is concluded that ideal areas for timber harvesting are currently restricted to places far from the market, and with low opportunity costs (ranging between ≤ $0 ha -1 year -1 and $500 ha -1 year -1 ).

The Impact of Near Natural Forest Management on the Carbon Stock and Sequestration Potential of Pinus massoniana (Lamb.) and Cunninghamia lanceolata (Lamb.) Hook. Plantations

Quantifying the impact of forest management on carbon (C) stock is important for evaluating and enhancing the ability of plantations to mitigate climate change. Near natural forest management (NNFM) through species enrichment planting in single species plantations, structural adjustment, and understory protection is widely used in plantation management. However, its long-term effect on forest ecosystem C stock remains unclear. We therefore selected two typical coniferous plantations in southwest China, Pinus massoniana (Lamb.) and Cunninghamia lanceolate (Lamb.) Hook., to explore the effects of long-term NNFM on ecosystem C storage. The C content and stock of different components in the pure plantations of P. massoniana (PCK) and C. lanceolata (CCK), and their corresponding near natural managed forests (PCN and CCN, respectively), were investigated during eight years of NNFM beginning in 2008. In 2016, there was no change in the vegetation C content, while soil C content in the 0–20 cm and 20–40 cm layers significantly increased, compared to the pure forests. In the P. massoniana and C. lanceolata plantations, NNFM increased the ecosystem C stock by 31.8% and 24.3%, respectively. Overall, the total C stock of soil and arborous layer accounted for 98.2%–99.4% of the whole ecosystem C stock. The increase in the biomass of the retained and underplanted trees led to a greater increase in the arborous C stock in the near natural forests than in the controls. The NNFM exhibited an increasingly positive correlation with the ecosystem C stock over time. Long-term NNFM enhances ecosystem C sequestration by increasing tree growth rate at individual and stand scales, as well as by likely changing the litter decomposition rate resulting from shifts in species composition and stand density. These results indicated that NNFM plays a positive role in achieving multi-objective silviculture and climate change mitigation.

Use of selected allowable cut indicators in near-natural forest management

The objective of this paper is to evaluate the possibilities of using selected allowable cut indicators in near-natural forest management by supplementing two indicators to present allowable cut indicators. Namely it is 1/30 of forest stand growing stock of the last three age classes and higher and 1/40 of forest stand growing stock of the last four age classes and higher. These indicators are compared with the allowable cut indicator 1/20 of forest stand growing stock of the last two age classes and higher which in relation to the forest law can be used in the present control of cuttings. The evaluations were carried out at selected five forest user’s units where near-natural forest management is applied. The results confirmed that it is not possible to use the indicator 1/20 in environmentally sound silvicultural systems. The results demonstrated the continuity of cuttings if the indicator 1/30 was used