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Mufarhatun N, Susilowati A, Hilwan I, Arrofaha N, Yulita KS, Dwiyanti FG, Hidayat A, Kamiya K, Rachmat HH. 2023. Leaf morphological traits of nine major tropical trees of Shorea species (Dipterocarpaceae). Biodiversitas 24: 1704-1712. Shorea is the largest genus in the Dipterocarpaceae family and has high leaf morphological variations among its species, which causes difficulties in field identification. Therefore, information on the specific characteristics of the leaf morphology of each species is needed. This study aimed to examine and discriminate leaf morphological traits at both mature and sapling stages of nine Shorea species, namely Shorea balangeran (Korth.) Burck, S. leprosula Miq., S. mecistopteryx Ridl., S. multiflora (Burck) Symington, S. ovalis (Korth.) Blume, S. pinanga Scheff., S. platyclados Slooten ex Endert, S. selanica (Wight & Arn.) Blume, and S. stenoptera Burck. The leaves of 90 mature trees growing in the Dramaga Research Forest (DRF) and Gunung Dahu Research Forest (GDRF) as well as the leaves of 180 saplings growing in the nursery of Forest Research and Development Center (FRDC) were observed. Leaf traits, leaf color, and chlorophyll content were assessed on 3 leaves from each mature tree and 5 from each sapling collected. Furthermore, comparative analysis using F independent test in the one-way analysis variance (ANOVA), multivariate analysis using Principal Component Analysis (PCA), and Hierarchical Cluster Analysis were used in this study. The results showed that 8 of the 11 measured morphological traits were identified as the quantitative leaves morphological differentiators, namely Leaves Width (LW), Lamina Length (LL), the length between the largest Leaves Point (LP) with the base of the leaves, angle of leaves vein (SD), Petiole Length (PL), number of leaves vein (LB), breadth of the leaves (WL), and the Circumference of the Leaves (CL). In addition, the results of cluster analysis showed the nine Shorea spp. are clustered into two major groups. Group 1 consisted of species, S. stenoptera, and S. mecistopteryx, while the remaining are included in Group 2. Our findings conclude that the eight leaf morphological traits obtained from this study are useful as additional characters to distinguish the nine Shorea species in the field.

Susilowati A, Novriyanti E, Rachmat HH, Rangkuti AB, Harahap MM, Ginting IM, Kaban NS, Iswanto AH. 2022. Foliar stomata characteristics of tree species in a university green open space. Biodiversitas 23: 1482-1489. Stomata, a gas regulatory system of leaves, provide a great chance to investigate the interaction between plants and their environment. Stomata consist of surrounded by two guard cells. Stomata are found in all parts of the plant that are exposed to the air, especially the leaves. In identifying a plant species, it is necessary to have epidermal characteristics such as stomata to complete the taxonomic data. Several studies have been conducted on the type of stomata on the leaves of some dicotyledonous and monocot plants, but not many have reported similar studies on green space. Universitas Sumatera Utara (USU) campus also plays an important function as green space (GS) in Medan City due to its richness in tree collection number and species. In line with the effort in o maximizing the role of trees as the core element of green space, exploring the characteristics of stomata is important to conduct. Therefore, this study aimed to analyze the leaf stomata characteristics of several tree species in the green open space of the USU campus. A total of 83 tree species were taken for their leaves to investigate the stomata characters. Three healthy mature leaves on the lower part of newly grown branches were collected from each plant. The replica and the nail polish method were employed for stomata slice making. The stomata type, length, wide, density and distribution were observed. The result showed that 83 tree species in the USU campus have varied stomata types, with the percentage were highest characteristic found in paracytic (91.46%), followed by anomocytic (6.02%), anisocytic (1.20%), and diacytic (1.20%). The longest stomata were observed in Antidesma bunius (32.04 ????????). The widest stomata were noticed in Garcinia mangostana (37.62 ????????). Meanwhile, the shortest and narrowest stomata were found in Shorea laevis, which were 5.43 ???????? and 3.72 ????????, respectively. The species with the highest stomatal density was Schleichera oleosa (4294 mm-2). According to the study, the tree species at USU generally have high stomata density, length, and width, making them more suitable for green space. Species with a high number and density of stomata and a large size are much more likely to adsorb pollutants such as carbon monoxide.

Yulita KS, Susilowati A, Rachmat HH, Susila, Hidayat A, Dwiyanti FG. 2022. Molecular identification of Eurycoma longifolia Jack from Sumatra, Indonesia using trnL-F region. Biodiversitas 23: 1374-1382. Eurycoma longifolia Jack (Simaroubaceae) or pasak bumi is a popular medicinal plant from Southeast Asia’s rainforests that is used as an aphrodisiac, antimicrobial, anti-malaria antidiabetic, antiulcer, and anticancer agent. However, the increasing demand for this species for medicinal industries has led to illegal export in Indonesia. This study aimed to determine the specific genetic variation and develop DNA barcode using trnL-Fregion for E. longifolia originating from Sumatra, Indonesia. Twenty-two samples of the species were collected from four locations in Sumatra. An aligned sequence of the trnL-Fwas 960 bp with an A/T rich region (A: 30.2%, T: 34.5%, C: 16.7%, and G: 18.7%). The homology search using BLASTn of the GenBank NCBI showed that the nucleotide composition of the species was similar (99.9%) to the partial trnL-Fregion of E. longifolia MH751519 and E. apiculata GU593014. Close examination of the gene structure and composition showed that the DNA sequences have five nucleotides variations that were not possessed by the reference E. longifolia, and other taxa used. The obtained variations occurred mostly in the trnL intron region, and the phylogenetic analysis showed that the correct identity of the species of the samples by their position was at a similar clade as the other accessions of E. longifolia.

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.

Iswanto AH, Siregar YS, Susilowati A, Darwis A, Hartono R, Wirjosentono B, Rachmat HH, Hidayat A, Fatriasari W. 2019. Variation in chemical constituent of Styrax sumatrana wood growing at different cultivation site in North Sumatra, Indonesia. Biodiversitas 20: 448-452. Kemenyan Toba (Styrax sumatrana) is known as endemic resin-producing trees that naturally grow in North Sumatra and distributed throughout five districts within the province. Different growing site may constitute to different characteristics of the species, e.g. morphological differences, chemical constituent, bioactive substances, etc. Different characteristics of wood chemical constituent are an important factor determining further utilization and potential use of wood in wider spectrums. Information about wood chemical constituent of Styrax sumatrana growing from different site has not been determined yet. Therefore, the objective of this research was to analyze the characteristics of chemical constituent of Styrax sumatrana wood originated from North Tapanuli and Pakpak Bharat according to axial direction of stem (bottom, middle, and top). Chemical properties such as hollocelulose, α-cellulose, hemicellulose, Acid Soluble Lignin (ASL), acid insoluble lignin (AIL), and non-structural component (extractive content in ethanol benzene 1: 2 and ash content) were observed. Results showed that different growth location would yield in different wood chemical constituent. The wood chemical constituent from North Tapanuli and Pakpak Bharat were 52.72 and 69.80% (hollocelulose), 25.94 and 39.87% (α-cellulose), 26.78 and 29.92% (hemicellulose), 5.49 and 4.33% (Acid Soluble Lignin), 4.37 and 20.43% (Acid-Insoluble Lignin), 10.95 and 2.42% (extractive content), 1.37 and 0.8% for ash content.

Elfiati D, Delvian, Hanum H, Susilowati A, Rachmat HH. 2021. Potential of phosphate solubilizing fungi isolated from peat soils as inoculant biofertilizer. Biodiversitas 22: 3042-3048. Phosphate-solubilizing fungi are the microbes that have the ability to dissolve insoluble phosphate and made it available for plants. Therefore, the purpose of this study was to obtain the phosphate-solubilizing fungi from peat soils. Peat soil samples were taken in a composite at a depth 0-20 cm from the peat ecosystem in Nagasaribu Village, Lintong Nihuta Sub-district, Humbang Hasundutan District, North Sumatra, Indonesia. Soil samples were isolated to obtain phosphate-solubilizing fungi using the Pikovskaya selective medium. The obtained isolates were tested for their ability to dissolve phosphate qualitatively by calculating the dissolution index values and quantitatively by calculating the available phosphorus on Pikovskaya medium by using four phosphate sources, namely Ca3(PO4)2, AlPO4, FePO4, and phosphate rock. Total of 12 isolates of phosphate-solubilizing fungi was obtained during the present study. Based on the results of qualitative and quantitative testing, all 12 isolates have the ability to release phosphate from the four tasted phosphate sources. The qualitative test obtains dissolution index values that vary from 2.55 to 4.25, while quantitatively, the isolates were able to dissolve phosphate in the value range from 17.77 ppm to 69.86 ppm. The top five fungal isolates with highest phosphate-solubilizing potential were FG5, FG8, FG9, FG11, and FG12. Based on molecular identification, these five isolates were identified as Aspergillus niger.

Susilowati A, Rangkuti AB, Rachmat HH, Iswanto AH, Harahap MM, Elfiati D, Slamet B, Ginting IM. 2021. Maintaining tree biodiversity in urban communities on the university campus. Biodiversitas 22: 2839-2847. Many universities worldwide have green spaces (GS) as an integral part of their campuses because of significant benefits for ecological function and urban communities. University of Sumatera Utara (USU) campus is located in urban area of Medan city, Indonesia, with a total area of 120 hectares. The campus offers various outdoor spaces for resting, sports, playgrounds and other psychological benefits. The campus also offers vital benefits for its surrounding environment, such as improving air quality and ensuring pleasant climatic conditions and biodiversity. One of the important functions of USU GS is to become an area for preserving tree diversity in urban communities, which in busy urban communities is sometimes a little overlooked. This research aimed to identify the species diversity, abundance, utilization, and conservation status of trees across 120 hectares of USU Campus using the field inventory method. Results revealed a total of 7333 individual trees of 121 species from 37 families. The most common tree species is Swietenia macrophylla (18.37%), while the dominant families are Fabaceae. Margalef index and the Shannon-Wiener diversity index reaching 13.48 (good) and 3.41 (high). Based on the utilization status, 55.43% of the tree species were wood producers, 45.34% were pollutant absorbers, while the lowest percentage functioned as latex producers (0.12%). About 70 species (57.85%) were native species, while 51 species (42.15%) were exotic. According to the International Union for Conservation of Nature (IUCN), 50 species (41.33% %) were listed as the least concern status, 8 species (6.61%) with a vulnerable status, 4 species (3.30%) with a near-threatened status and 2 species (1.66%) with and endangered status. The result from this study also showed that GS at USU not only performed its main function as a shade or an oxygen producer (environment services) but also maintained the tree biodiversity and a means of ex-situ conservation for many trees species. Trees threatened by anthropogenic activities, particularly tree felling for infrastructural developments were still found in the campus area. Therefore, sustainable conservation efforts should be geared towards ensuring the continued existence of the trees to maintain their ecological functions

Rachmat HH, Subiakto A, Susilowati A. 2018. Mass vegetative propagation of rare and endangered tree species of Indonesia by shoot cuttings by KOFFCO method and effect of container type on nursery storage of rooted cuttings. Biodiversitas 19: 2353-2358. The Forestry Research and Development Agency (FORDA) and The Advance Research of Komatsu Ltd have developed a mass propagation technique using shoot cuttings, namely KOFFCO system (Komatsu-FORDA Fog Cooling System). KOFFCO system controls environmental factors (temperature, humidity, and light intensity) to produce high percentage of rooted cuttings. The seed production of dipterocarp species is unreliable and unpredictable. Thus, vegetative propagation is an alternative means for producing planting materials of dipterocarp species. An attempt was made to produce rooted cuttings of rare and endangered dipterocarp and non-dipterocarp species of the Indonesian native trees, for further use in both reforestation and plantation programs. In fact, this study attempts to answer two specific research questions: (i) What is the potential of KOFFCO system as a vegetative mass propagation technique for Indonesian dipterocarps and non-dipterocarps? (ii) What is the effect of container types on long-term post-nursery storage of dipterocarp planting stock? To answer the first question stated above, vegetative propagation through shoot cuttings of 24 species belonging to 7 genera of dipterocarps and 13 species belonging to 12 genera of non-dipterocarps was attempted (>30.000 cuttings, in total), using KOFFCO system. The results showed that KOFFCO is an efficient innovative technology for the successful mass propagation from cuttings. 100% root formation obtained for Nauclea orientalis, Anotephalus macrophyllus and Ficus sp. To find the answer for the second question, storage experiments and growth observations of the planting stock of selected dipterocarp species was performed, using three different types of containers. Rooted cuttings of six species of dipterocarps with same germination date were tested in each type of the container. The result showed that medium sized square and medium sized round containers produced an average height increment of 19.92 cm and 21.58 cm, respectively, in a year, while small sized square containers produced only 13.94 cm height increment. Both square and round shaped containers are appropriate for short term storage of planting stock, while small containers are more appropriate for storing planting stocks or seedlings for a longer period.

Rachmat HH, Susilowati A, Elfiati D, Hartini KS, Faradillah WN. 2017. Short Communication: Strong genetic differentiation of the endemic rosin-producing tree Styrax sumatrana (Styracaceae) in North Sumatra, Indonesia. Biodiversitas 18: 1331-1335. Styrax sumatrana is an economically important rosin-producing tree endemic to North Sumatra, Indonesia. Distribution of this species is very limited, and the high rate of forest degradation in Sumatra is increasing the necessity for conservation. To quantify genetic variation and population structuring, we collected individuals from 3 populations namely Pakpak Bharat, Humbang Hasundutan (Humbahas) and Tapanuli Utara in which each of the population was represented by 10 individuals. However, the successful rate of amplification was varied among populations and for later analysis, we only took an account those sequences showing clear electropherograms and disposed those which showed ambiguity. We sequenced trnL-trnF chloroplast DNA (cpDNA) region yielded 941 bp after alignment. The trnL-trnF assigned the species into 4 haplotypes in which Pakpak Bharat was differentiated significantly and not shared any similar haplotypes with two others populations. Humbahas and Tapanuli Utara was shared one common haplotype. Mean nucleotide diversity at silent sites ranged 0 - 3.33 x 10-3, while nucleotide diversity at non-synonymous site ranged 0 - 5.9 x 10-4. Strong genetic differentiation was also found among 3 origin populations, with the highest pairwise genetic differentiation found on Pakpak Bharat and Tapanuli Utara (FST= 0.80952). Clear and apparent genetic structuring was possibly caused by geographical barriers such as highland and mountain ranges (Bukit Barisan mountain ranges) which acted as effective barriers to gene flow among population. The findings suggest that conservation efforts should focus on every population because each of the population maintains distinct genetic identity.

Elfiati D, Susilowati A, Modes C, Rachmat HH. 2019. Morphological and molecular identification of cellulolytic fungi associated with local raru species. Biodiversitas 20: 2348-2354. This study is aimed to isolate and identify cellulolytic fungi from different local Raru species in Central Tapanuli, North Sumatra, Indonesia. Cellulolytic fungi are fungi that can degrade natural polymer materials such as cellulose. The fungal species were isolated from soil under three local raru species. The samples inoculating (1 mL) from serial dilutions (10-2 to 10-5) on Carboxy Methyl Cellulose (CMC) plates. The plates were incubated at 28 ̊C for one week, then the fungal colonies were observed and pure cultures were maintained. Fungi with cellulolytic activity were characterized by the formation of clear zones around the colonies on CMC media plus congo red (0.1%). The identification of fungi was carried out by molecular identification of the isolated fungi at the species level. The extracted fungal DNA was amplified by PCR using specific internal transcribed spacer primer (ITS1/ITS4). The PCR products were sequenced and compared with the other related sequences in Gen Bank (NCBI). 20 isolates were successfully isolated and nine isolates had cellulolytic activity. Six fungal species from 20 isolates were identified as: Aspergillus sp., Penicillium sp., Aspergillus terreus, Penicillium mariae-crucis, Aspergillus tanneri and Penicillium citrinum. The results showed that Aspergillus terreus was the most abundant fungus obtained from all the raru stand.

Susilowati A, Rachmat HH, Elfiati D, Kholibrina CR, Kusuma YS, Siregar H. 2019. Population structure of Cotylelobium melanoxylon within vegetation community in Bona Lumban Forest, Central Tapanuli, North Sumatra, Indonesia. Biodiversitas 20: 1681-1687. In many forests stand, Cotylelobium melanoxylon is hard to find in the wild at present day because its bark has been intensively harvested for traditional alcoholic drink and sold by kilogram in traditional market in North Sumatra and Riau. This activity has put the species into serious threats of their existence in their natural habitat. We conducted study to determine the population structure of the species at seedling to tree stage in Bona Lumban Forest, Central Tapanuli. We used purposive sampling by making line transect at forest area where C. melanoxylon naturally grow. There were four transects with each transect consisted of five plots in which nested plots were established to record data at four growth stages, resulting in 80 plots in total. The result showed that the Important Value Index (IVI) for C. melanoxylon were 66.33, 17.65, 11.82, 12.90; Diversity Index (H) were 2.9, 1.90,2.88, 2.53 and 12.90, Index of evenness (E) were 0.844, 0.534, 0.85, 0.935 and the Index of Richness (R) were 5.71, 7.13, 5.37, 3.67 for the stage tree, pole, sapling, and seedlings, respectively This result demonstrates that C. melanoxylon still grows naturally in Bona Lumban at all stages from tree to seedling. However, there might be a problem in its natural regeneration as there is big difference of its high IVI at tree stage compared to IVI value for its younger stages. The regeneration status of C. melanoxylon was also classified into fair. This might be generated from the condition that the existing mature trees remaining were no longer productive and healthy due to excessive harvesting for its bark.

Subiakto A, Rachmat HH, Sakai C. 2016. Choosing native tree species for establishing man-made forest: A new perspective for sustainable forest management in changing world. Biodiversitas 17: 620-625. Establishment of tree plantation on degraded lands and forest clearly favored some exotic species such as Gmelina arborea, Acacia, and Eucalyptus. High productivity, less harvesting time, and deeper silvicultural knowledge are the beneficial factor for choosing those exotics species. However, the use of a wide variety of native tree species becomes more significantly important in reforestation projects due to the greater biodiversity benefits and widerenvironmental services. This research was carried out as a multiyear observation and continuous experiment to value how native tree species can be prospective alternatives in providing and supporting human need. The performances of two native Indonesian Shorea species, Shorea leprosula and Shorea selanica, were evaluated at a dipterocarp planting trial in two different sites in Indonesia. Growth data was obtained from 15 and 17 years old plots, twelve 100 m X 100 m square plots on mineral soils (Gunung Dahu Experimental Forest/GDEF, Bogor) and eight resembled plots on frequently flooded peat land (PT. Arara Abadi/PT. AA, Riau). Survival rates were varied, ranged from 36-77%, diameter at breast height from 13.7-24.9 cm, tree height from 10.8-16.9 m, mean volume from 0.119m3/tree-0.567 m3/tree, and total volume from 79.420 m3/ha-215.412 m3/ha. Growth rates of planted saplings were affected by species, site and spacing distance. The development of man-made dipterocarps forest in the tropic, especially in South East Asia can be as prospective as developing an exotic fast growing plantation. Eventhough in situ conservation would give the most benefit in conserving genetic resources of native tree species, establishing man-made dipterocarp forest still have higher environmental value than using exotic tree species such as acacia. Moreover, establishing man-made dipterocarp forest is considered more environmental friendly and possess lower to no risk of species invasion compare to those of developing exotic trees plantation.

Rachmat HH, Subiakto A, Kamiya K. 2016. Genetic diversity and conservation strategy considerations for highly valuable medicinal tree of Taxus sumatrana in Indonesia. Biodiversitas 17: 487-491. Genetic variation is considered to be the key factor for longterm survival of the species. The recognition of the existing genetic diversity is the preliminary phase in development of an effective strategy for conservation of forest tree species. Taxus sumatrana or is confined to grow naturally only in Asia, it is a rare and endangered species that in several Asian countries needs both ex situ and in situ protection program. In its natural distribution, T. sumatrana is the only Taxus species that reached its southernmost distribution to Sumatran forest-Indonesia and locally named as Sumatran Yew. The objective of this research was to determine the genetic variation of T. sumatrana as baseline information for designing conservation strategy of the species. Leaves samples were collected from two natural population of T. sumatrana in Mt. Kerinci (Sungai Penuh, Jambi) and Mt. Dempo (Pagaralam, South Sumatra), both sites are located along Bukit Barisan Mountain Ranges of Sumatra. We sequenced two non-coding chloroplast DNA (cpDNA) regions of trnL-trnF and psbC-trnS that each yielded 808 bp and 1092 bp, and rbcL gene of 523 bp, in which the total length covered 2423 bp. Surprisingly, we found no variation for all individuals and population, which means that the species is similar and both populations are not genetically structured. This study also revealed on how a proper conservation strategy should be practiced for the species as we know that without a sufficient amount of genetic variation, a population cannot evolve in response to changing environmental conditions. In situ conservation program is a must that can maintain the existence of the species while at the same time keeping the sustainability of the entire systems; in other side ex situ conservation strategy can take place as an additional effort to secure the genetic resources in case of the catastrophic events that might diminish their limited natural habitat.