Pinus merkusii Jungh et de Vriese, known as Tusam or Sumatran pine, is the only pine that grows naturally in the south of the Equator with its natural distribution found in Indonesia, the Philippines, Myanmar, Thailand, Laos, Cambodia, and Vietnam. The Sumatran pine is an economically and ecologically important species in Indonesia that covers three native strains, Aceh, Kerinci, and Tapanuli. The resin tapping of the pine has been practiced for hundreds of years while its timber has long been commercially used for various purposes. Although the pine is known as highland species, its adaptability on a wide spectrum environment makes it suitable for various restoration and rehabilitation purposes both in lowland and highland sites. Its high commercial values have also made the species be massively planted in pine plantations outside their natural distribution in Sumatera (i.e., in Java and Sulawesi island). This paper will review the current condition of Sumatran pine and its potential as a restoration and rehabilitation species and delivering its natural and artificial distribution map in Indonesia. In addition, the paper will also show the genetic variability of the species, determine the current innovative practices in silvicultural aspect both at nursery and plantation scales, describe tree improvement program, including its role in agroforestry practices, pine product both timber and non-timber, and its potential resources in relation with climate change mitigation management.

Susilowati A, Elfiati D, Rachmat HH, Yulita KS, Hadi AN, Kusuma YS, Batu SAL. 2020. Vegetation structure and floristic composition of tree species in the habitat of Scaphium macropodum in Gunung Leuser National Park, Sumatra, Indonesia. Biodiversitas 21: 3025-3033. Scaphium macropodum (Miq.) Beumee Ex K Heyne is a member of Malvaceae tree species and globally recognized as malva nut and locally known as ‘kembang semangkok’, ‘tempayang’, ‘merpayang’ or ‘kepayang’. The nut of S. macropodum has many benefits for medicinal purposes, yet destructive extraction of this tree species has led them to extinction. Among its natural distribution in Indonesia, North Sumatra Province, Indonesia is known as its original range, but there is limited information about the existence of this species. This study aimed to determine the vegetation structure of some tree species in the habitat of S. macropodum in Sikundur, Gunung Leuser National Park, Sumatra, Indonesia. Purposive sampling technique was employed by creating line transect at some forest areas where the population of S. macropodum is known to grow naturally. Four line transects with each transect consisting of five plots with nested plots within were established to record data at four growth stages, resulting in 80 plots in total. The results showed that the Important Value Index (IVI) of S. macropodum within the floristic community at the studied area was 21.98, 13.85, 27.30, and 39.60 for tree, pole, sapling, and seedlings stages, respectively. The Shannon-Wiener Diversity Index (H) were 3.80, 3.70, 3.06 and 2.45, Index of evenness (E) are 0.94, 0.92, 0.86, 0.77 and the Index of Richness (R) are 11.76, 10.73, 6.59, 4.10 for tree, pole, sapling, and seedlings stages. This result suggests that the natural population of S. macropodum in Sikundur forest was still in good condition at all stages from tree to seedling.

Susilowati A, Rachmat HH, Elfiati D, Hasibuan MH. 2019. The composition and diversity of plant species in pasak bumi’s (Eurycoma longifolia) habitat in Batang Lubu Sutam forest, North Sumatra, Indonesia. Biodiversitas 20: 413-418. Pasak bumi (Eurycoma longifolia Jack) is one of the most popular medicinal plants in Indonesia. Currently, E. longifolia is being over-exploited due to its potential and popularity as herbal medicine and its high value in the market. Therefore, the study on the population structure of the species and habitat characterization is required to ensure successfulness of conservation of this species. The study was carried out in lowland forest, located in Limited Production Forest within the Register Number 40, situated administratively in Papaso Village, Sub-District of Batang Lubu Sutam-Padang Lawas, North Sumatra, Indonesia. Batang Lubu Sutam forest is known as a source of pasak bumi material in North Sumatra. Every year tons of pasak bumi are collected from this forest and exported to Malaysia and surrounding countries. Due to illegal harvesting for its roots, pasak bumi has been seriously depleted in some areas in Batang Lubu Sutam forest. Therefore, current data on its population are needed for conservation effort of Batang Lubu Sutam's pasak bumi. The objectives of this study were to assess the structure of forest where pasak bumi grows and to determine the correct management for sustainability the future stocks. Vegetation analysis was carried out purposively in four transect belts, each consisting of five quadrats or plots. The results showed that the Importance Value Index of pasak bumi at seedling, sapling, pole and tree stages was 21.26%, 9.147%, 0, and 0 respectively. The Shannon Diversity Index (H) ranged between 3.050 and 3.220 and was inside its common value distribution. The evenness index was high, more than 0.85, at all stages of plant growth. The disappearance of pasak bumi at pole and tree stages indicates threatening condition for the sustainability of pasak bumi in the study sites because of excessive harvesting.

Susilowati A, Rachmat HH, Elfiati D, Hidayat A, Hadi AN, Zaitunah A, Nainggolan D, Ginting IM. 2021. Floristic composition and diversity at Keruing (Dipterocarpus spp.) habitat in Tangkahan, Gunung Leuser National Park, Indonesia. Biodiversitas 22: 4448-4456. Dipterocarpus spp., or locally known as Keruing, is a wood-producing tree and has high economic value. Keruing also produces derivative products in oil and oleoresin, which are widely used as raw materials for medicines and perfumes. Keruing natural population has been severely declining caused by habitat alteration and also over exploitation. Therefore, information on the composition and diversity of the floristic community at their habitat is important as an initial step in designing conservation actions. This study aims to determine the floristic composition and diversity at the keruing habitat in the Tangkahan area, Gunung Leuser National Park (Gunung Leuser NP). A line transect has been used to establish a purposive sampling in particular forest areas where the population of the keruing is known to grow naturally. Four line transects, each with five nested plots, totaling 110 plots, were established to gather data at four growth stages. The results found 47 species at the seedling stage, 43 species at the sapling stage, 48 species at the pole stage and 65 species at the tree stage. There were three species of keruing in the research location, namely Dipterocarpus haseltii, Dipterocarpus costulatus and Dipterocarpus elongatus Korth with low IVI values ??at each stage. D. haseltii was only found at the seedling, pole and tree stage with IVI values ??of 0.32, 0.30, and 6.90, respectively. D. costulatus was only found at the tree level with an IVI value of 3.43, while D. elongatus found at the sapling and tree stage with an IVI of 0.30 and 3.42, respectively. The diversity index in the research location was in the medium category at the seedling, sapling, and pole levels with a value of 2.96, 2.86, and 2.92, respectively and was classified as high at the tree level with a value of 3.18. The evenness index (E') in all growth stages is high or evenly distributed with the value of E' > 0.75. The species diversity in research location classified into medium-high category although in each stage showing dynamic on species domination. Disturbed habitat due to illegal logging and land conversion caused a problem on keruing regeneration. Conservation efforts, including active monitoring keruing occurrence, ex-situ conservation, and artificial regeneration, are needed to avoid keruing from extinction.

Gunung Dahu Research Forest (GDRF) is a 250 ha tropical degraded land reforested by native dipterocarps species. The reforestation success was valued by evaluating the planted trees’ growth performance, their potential timber stock, natural regeneration capacity, soil improvement, biological interdependence, and environmental services. This scientific report used a combination of literature review and also primary data processing to describe the reforestation success within the area. A hilly species of Shorea platyclados showed the best growth performance with its average diameter and height of 43 cm and 23 m, respectively, with its mean diameter annual increment of 2.1 cm/year and the predicted standing stock at 220 m³/ha. Six Shorea species were identified to show their natural regeneration capacity and the occurrence of ectomycorrhizal fruiting bodies, predominantly by the genus Rusula, determined the establishment of biological interdependency at the site. Reforestation improved soil organic matters as revealed by high soil porosity (51.06–52.32%) and infiltration rate (120–155.33 mm/h). The reforested landscape also ensures a continuous water supply and provides an economic benefit for the community. Thus, planting native trees for reforesting degraded tropical landscapes is prospective and may deliver multiple benefits in an ecological and economic view.

Aleurites moluccana or locally known as kemiri or candlenut is domesticated multipurpose tree species found in Indonesia, particularly in North Sumatra. As one of high economic value commodities, candlenut can be adopted as agroforestry species, windbreak, soil immobilization and land rehabilitation for critical land that can improve community livelihood with a variety of benefits. Information regarding seed characteristics of the candlenut in North Sumatra Province and its germination strategies is still limited, whereas this information are needed to support candlenut cultivation. Therefore, this research was conducted to obtain information on morphology and germination process of the seed of candlenut. Direct measurement and observation of seed were quantified to observe the seed morphology. The germination process is also quantified through direct observation. The results of seed morphology showed that the candlenut had rough elliptical shell shape with about 6.08 cm in diameter and the shell thickness was approximately 2.56 cm. Germination process took 4-5 months with hypogeal germination type.