Habitat Preferences , Distribution Pattern , and Root Weight Estimation of Pasak Bumi

Pasak bumi (Eurycoma longifolia Jack) is one of non timber forest products with “indeterminate” conservation status and commercially traded in West Kalimantan. The research objective was to determine the potential of pasak bumi root per hectare and its ecological condition under natural habitat. Root weight of E. longifolia Jack was estimated using simple linear regression and exponential equation with stem diameter and height as independent variables. The results showed that the individual number of the population was 114 with the majority in seedling stage with 71 individuals (62.28%). The distribution was found in clumped pattern. Conditions of the habitat could o be described as follows: daily average temperature of 25.6 C, daily average relative humidity of 73.6%, light intensity of 0.9 klx, and red-yellow podsolic soil with texture ranged from clay to sandy clay. The selected estimator model for E. longifolia Jack root weight used exponential equation with stem height as independent variable using 0,010 the equation of Y= 21.99T and determination coefficient of 0.97. After height variable was added, the potential of E. longifolia Jack minimum root weight that could be harvested per hectare was 0.33 kg.


E. longifolia
is one of non timber forest product is commercially traded in in West Kalimantan.According to Rifai (1975).E. longifolia Jack. is generally found in shrub or tree forms with height that can reach 10 m, odd pinnate compound leaves, yellow stem, hard tree bark and very bitter taste.Mardisiswojo and Harsono (1968) stated that E. longifolia Jack. is wild plant which mainly found in Sumatra and Kalimantan.All parts of the plant (root, stem, root bark, and leaf) are proved to be medicinal.Certain studies report that pharmacologically, E. longifolia Jack.contains anticancer compound (Nurhanan et al. 2005;Tee et al. 2007), anti-bacteria (Farouk & Benafri 2007), osteoporosis therapy for men (Effendi et al. 2012), cyto-toxic (Kuo et al. 2003;Kuo et al. 2004), aphrodisiac (Ang et al. 2003;2004), antileukemia, anti-malaria, and dysentery (Chan et al. 2005).Due to its various benefits, there has been a substantial increase in its demands for medicinal ingredients.The dry product is market at quite high price.According to the company data of UD Sumatra Pasak Bumi as the exporter of Jack.that E. longifolia base in Deli Serdang, the export price for chipped root is USD249.16kg .Meanwhile, the price for -1 extracts 1:200 is USD3242.85kg and extracts 1: 50 with the -1 price of USD1625 kg .The price has increased compared to the price in 2012 of the extracts 1:50 with the price of -1 USD375 kg and for extract 1:200 with the price about -1 USD900 kg (Sumatra Pasak Bumi 2013).Such high price has encouraged the increase exploitation of E. longifolia Jack in the forest since current harvesting relies only on wild E. longifolia Jack by means pulling out the roots.Destructive harvesting by root pulling should account for concern for the plant's sustainability (Farooquee et al. 2004;Kala et al. 2004;Ghimire et al. 2005).Since the natural habitats of E. longifolia Jack are found only in certain regions of Indonesia (Sumatra and Kalimantan), it brings about the concern for its extinction.Therefore, E. longifolia Jack requires conservation efforts and silviculture technique to maintain the existence.Moreover, in 2001, Malaysia has declared E. longifolia Jack as scarce plant with "indeterminate" status (Rifai 1992).Zuhud and Haryanto (1991)  Currently, there are no national and local regulations covering the management and protection of E. longifolia Jack.Though E. longifolia Jack has economic value, there is no quota regulating its trade.Furthermore, there is a scarcity of research related to its habitat preferences.Therefore, to achieve sustainable utilization, assessments on E. longifolia Jack's habitat preferences, distribution pattern, and root weight estimation are required to determine the sustainable harvesting quota.This research had the objectives to assess the habitat preferences, distribution pattern, and estimation of root weight per hectare of E. longifolia Jack to determine the correct management and sustainable harvesting quota.

Methods
The research was conducted in the Protected Forest of Ambawang-Pemancingan Mountain in Kubu Raya District, West Kalimantan Province.Data collection to assess the potential of E. longifolia Jack was carried out using line plot sampling method, consisted of 5 lines and divided into plots of sized 20 × 20 meter.An observation plot of 1 ha was assumed to be able to describe the population condition and the potential root weight.Data recorded in each plot consisted of: total number of individual plant, height, stem diameter, and habitat conditions (temperature, humidity, and light intensity).

Data analysis
Variables used to estimate the potential of E. longifolia Jack were root weight as dependent variable, and diameter and height as independent variables.These variables are then inputted into the following equations as shown in Equation [1], Equation [2], Equation [3], and  Equation [4 Equation [4], and data analysis, correlation and proper equation could be obtained.The proper equation was 2 determined from the highest determination coefficient (R ).
Distribution pattern Morrisita method was used to assess the distribution pattern of E. longifolia Jack.Morissita standard has an interval value from -1.0-1.0 with the limit of confidence interval of 0.5 and 0.5 therefore with Ip value, plant distribution would be obtained, where: Ip = 0, means random distribution pattern Ip > 0, means clumped distribution pattern Ip < 0, means uniform distribution pattern

Results and Discussion
Habitat condition of E. longifolia Jack E. longifolia Jack has a wide range of topographic distribution.Based on the physical condition in each plot, in general E. longifolia Jack was found at elevation between 5-410 m asl, where it tent to increase with elevation (Figure 1).Whereas based on collection material found in Herbarium Bogoriense, E. longifolia Jack can be found at elevations of 0-700 m asl.
Elevation is related to the distribution of climate factors Jack based on elevation (meter above sea level).E. longifolia such as temperature, rainfall, humidity, and sunlight intensity.All these factors affect the ecosystem type distribution and hence affect plants' distribution (Ewusie 1990).The ecological parameters observed in the field that corresponded to its elevation were: daily average o temperature of 25.6 C, daily average relative humidity of 88.4%, and light intensity of 0.9 klx.These results were similar to those of Ginting (2010) in Medan who obtained o daily average temperature of 23.7 C, daily average relative humidity of 90.8%, and light intensity of 1.136 klx.Elevation was found to be inversely correlated with temperature and light intensity and positively correlated with relative humidity.This confirmed with Handoko (1993) who explains that lower humidity corresponds to lower temperature and vice versa.The higher the site, the lower the temperature and light intensity, which is caused by the less absorbance from the air.
Edaphic type of Protected Forest of Ambawang-Pemancingan Mountain varies from river banks to hillside and comprised of sandy alluvial, peat and red yellow podsolic soil.Results of the soil chemical properties revealed that the contained N-total, Phosphor (P), and Kalium (K) tent to be higher at depth of 0-30 cm as compared to depth of 30-60 cm.It is reasonable since the organic matter content in topsoil is larger than that from litter decomposition in topsoil.Soil having a pH of 4.98 at depth of 0-30 cm is classified as acid soil, and pH of 4.31 at depth of 30-60 cm is classified as very acid soil.Based on C organic and CEC according to the evaluation criteria of chemical properties, the fertility status of this land is categorized as low.On the contrary, according to Ginting (2010), the nutrient content of the growing site of E. longifolia Jack in Bukit Lawang Forest area is quite high.This indicated that E. longifolia Jack could grow in poor nutrient soil as well as in fertile soil.E. longifolia Jack could survive under lack of soil nutrient but do not prefer inundated soil.E. longifolia Jack was largely found in sloping land or hillside.Table 2 and Table 3 presented the chemical and physical properties of the soil samples analysis.
Analysis of the soil physical properties revealed that soil type of research site was categorized as red yellow podsolic (PMK) with clay to sandy clay texture comprised of 23.36-46.81%sand, 10.61-16.16%ash, and 37.43-67.03%clay.Meanwhile, soil structure has formed granular aggregates with size of 2.25-4.14mm and moderate aggregates stability with granule and crumbs size classes.
Analysis of the soil physical properties is presented in Table 4.
The acid soil characteristics with sandy clay texture matched the botanic data of pasak bumi in Herbarium Bogoriense, that E. longifolia Jack preferred acid soil and siltsilica (Rifai 1975).It is also similar with results of Ginting (2010) in Bukit Lawang Forest that soil components of E. longifolia Jack consisted of sand, ash and clay.Since the bulk -3 density is about 0.91-1.02g cm (standard of bulk density -3 1.1-1.6 g cm ), it is easier for plant roots and water to penetrate into soil layer and improved the soil for water and air fixation (Hardjowigeno 2007).Such soil condition enabled the taproots of E. longifolia Jack to perpendicularly penetrate into the soil layers.
Population condition of E. longifolia Jack According to Primack (1998), a stable population usually has specific age distribution comprised of young, mature, and old individuals.Very often, at certain class age if individuals, mainly young individual was not found or found in a very small number, showed a decreased in population.Inversely, seedlings and individuals found in large numbers suggested a stable condition and increase in population.
Based on data gathered from the 25 plots samples of 20 × 20 m (1 ha), E. longifolia Jack population were found almost in every plot (23 plots) with 114 individuals.Only 2 plots had no E. longifolia Jack, i.e., in line 1 plot 1 and in line 2 plot 4 due to the rocky condition and domination by bamboo and rattan.Population of E. longifolia Jack within observation lines is presented in Figure 2. Based on the structure of growth class in all plot lines, the total number of seedlings found was 71 individuals (62.28%), saplings 42 individuals (36.84%), and poles only 1 individual (0.87 %).Such E. longifolia Jack growth structure was ecologically normal since in natural forest the normal vegetation structure is indicated by inverted "J" curve.It means that in sequence, the number of seedlings should be greater than saplings, the number of saplings should be greater than poles, and the number of poles should be greater than trees.Growth structure of E. longifolia Jack population is presented in Figure 3.
The small numbers of individuals in sapling and pole stages having diameter class of 10-20 cm were caused by the high rate of exploitation of E. longifolia Jack roots.Over exploitation has led to scarcity since it caused the death of

E. longifolia
parental trees.According to Hussein et al. (2005), the propagation of E. longifolia Jack has so far relies on wild seed.Meanwhile, as recalcitrant plant, the viability tent to be low and took a long time to germinate since zygotic embryo is immature during dispersion.Seed with undeveloped embryo during dispersion would not germinate in normal condition and hence, would be categorized as dormant.Related to the morphology stage of immature embryo, this phenomenon is often classified as morphologically dormant.Copeland and McDonald (1995) suggest that recalcitrant seed has short life term period and it difficult to store due high to water content that lead to microbial contamination, easily degraded and lead to death.Moreover, the obtained values of the microclimate measurements were: temperature of 23.4-27.8C, relative humidity of 64-88.4%, and light intensity ofs 0.74-1.16klx.These measurements indicated that biologically the forest condition has medium temperature, high enough humidity, and quite low light o intensity.All these conditions had prolonged seed dormancy process in natural forest.In addition, the seeds had been attacked by fungi and rot hence inhibited the seedling growth on forest floor.
Based on class diameter and height structure of E. longifolia Jack, there was a tendency that the bigger the diameter and height class, the lower the population of E. longifolia Jack.Population of E. longifolia Jack was higher in diameter class of < 1 cm, with 62 individuals.For diameter above 5 cm only 1 individual was found with class diameter of 9 cm located at the peak of the mountain.Similarly, the highest population was found in class diameter of 1-2 m.The low number of population above 5 cm and height more than 3 m occurred due to the high rate of E. longifolia Jack root exploitation in class diameter of 10-20 cm.Histograms of E. longifolia Jack based on diameter and height class are presented in Figure 4 and Figure 5.   point namely stem and root tip.Meanwhile, for diameter growth, the cambium activity was responsible to enlarge the stem.Primary and secondary growth can occur simultaneously at the same time (Campbell et al. 2000).However, based on the analysis result of site area condition, E. longifolia Jack could survive under poor nutrient level of red yellow podsolic with very acid soil pH.They were frequently found in low slope or hillsides.These conditions signified that due to nutrient and water shortages, cell mitosis in secondary growth has decreased.Inversely, cell mitosis was more active as the plant adapted to the environment.The root grew deeper to absorb nutrient and water, causing the plants to increase in height in search for sunlight.Van Noordwijk and Purnomosidhi (1995) report that trees with vertical roots that were well-developed and have less lateral root, generally had slow initial growth.Murniati (2009) also reports that in fertile soil, tree root could easily absorb nutrient and water.In that case, it is not important to pile up on or allocate food stock (photosynthesis result) for new root growth.Most of food stocks were accumulated in the upper part of the soil, so that shoot-root ratio became higher.In the opposite scenario, it was estimated that this occurred on trees grew or planted in high elevation area (hillside or hilltop).
This justified the reason that root is the inseparable part of the plant and played an important role as well as the upper parts of the plant.The root functioned to absorb water and nutrients, while the stem functioned to distribute and utilize it during growth period.Besides, according to the concept of morphological balance or morphogenetic balance stated by Hellriegel in 1883 (de Willingen & van Noordwijk 1987) it is necessary to maximize root growth in order to gain better growth of upper plant parts.

Distribution pattern
The distribution of E. longifolia Jack was found in clumped pattern.E. longifolia Jack was commonly found close to the mother tree.Regardless of the effect of environmental and competition factors, this result was relevant to the conclusion of Barbour et al. (1987) that the distribution pattern of plant species tend to clumped since the seed fallen closed to their parents.According to Ewusie (1986), big and small plants are both competing against each other for light, mineral or space especially for habitat and also for water which was probably limited.The most critical was the competition among individuals of the same species due to common basic needs.Since E. longifolia Jack is growing closed to each other, the competition occurred among seedling individuals.Only small parts of the seedling could survive in adaptation.Individuals able to survive could grow to higher growth stage.This phenomenon explained the reason for the weaker grouping stage of E. longifolia Jack as the growth stage increased.Distribution pattern of E. longifolia Jack within the 5 observation in the Protected Forest of Ambawang-Pemancingan Mountain is given in   Table 5.

Conclusion
The research found as many as 114 individuals E. longifolia Jack in the study site, with the highest population found in seedling stage comprised of 71 individuals (62.28%).The highest density was found within the elevation range of 320-402 m above sea level with 40 individuals, with distribution found in clumped pattern.The habitat conditions o were characterized by average temperature of 25.6 C, daily average relative humidity of 73.6%, light intensity of 0.9 klx, and red-yellow podsolic soil with clay to sandy clay texture.The selected estimator model for E. longifolia Jack root weight used exponential equation with stem height as 0,010o independent variable with the equation of Y = 21.99T and determination coefficient of 0.97.After height variable was added, the potential of E. longifolia Jack minimum root weight available for harvesting per hectare was found to be 0.33 kg.The potential root weight available for harvesting was relatively low since the tree height structure was dominated by seedling and sapling growth stages.

Recommendation
In order to reduce the exploitation of E. longifolia Jack, sustainable harvesting quota should be determined and silvicultural technique for E. longifolia Jack should be developed.

Figure 1
Figure 1 Population distribution ofJack based on elevation (meter above sea level).E. longifolia

Figure 3
Figure 3 Growth class structure.Figure 2 Population of Jack found along the observation lines.

FigureFigure 6
Figure 4 Diameter class structure of Jack.population.E.longifolia stated that E. Jack is one of 41 medicinal plants which shoud be considered as main priority in research, breeding, development, and utilization.
The protected forest status was based on the Minister of Forestry Decree No. 121/Kpts-II/2003, covering a total area of 3.370 ha.It is positioned on

Table 5
Distribution pattern of E. longifolia Jack in protected forest of Ambawang Pemancingan Mountain I : Morrissita Distribution Index; Mu: Uniformity Index; δ Mc: Clumped Index; Ip: Morissita

Table 4
Soil physical properties in protected forest of Ambawang-Pemancingan Mountain