Inventarization of Zingiberaceae in The West Block Batang Toru Forest of North Tapanuli North Sumatra

. Zingiberaceae is one of the dominating plant family in West Block, Batang Toru forest region. According to preliminary survey, the forest is inhabited by many species of Zingiberaceae while information on its species richness is still limited. The aim of the study was to collect the species of Zingiberaceae in West Block, Batang Toru forest region, conducted from July to September 2018. Inventarization was conducted using exploration method, by exploring along designated tracking ways. The study found 18 species of Zingiberaceae belonging to 10 genera was obtained, two of them were Alpinia hansenii and Boesenbergia belalongensis were new record in Sumatra. From all species that was found, two species were known to live as epiphytes and the other 16 were terresterials. Zingiberaceae occur in varying habitats, starting from forest edge, open area with optimum sunlight and inside forest floor. The most species found belong to Globba and Amomum.


Introduction
Sumatra is the sixth largest island in the world and the second largest island in Indonesia after Borneo. The island of Sumatra has tropical forests that are rich in biodiversity. The species diversity in Sumatra's forests is comparable to that found in Borneo and Papua New Guinea and richer than that found on Java, Sulawesi and other small islands. Sumatra has 17 endemic plant genera and several spectacular and unique plant species such as Rafflesia arnoldi, the world's largest flower and Amorphophallus titanum, the world's tallest flower . The Batang Toru natural forest area is divided into two main blocks, namely the West block and the East block. The western block of Batang Toru forest has Dipterocarpaceae forest habitat types at medium and high elevations and mountain forest at low elevations, while the East Block Batang Toru forest has a pure stand forest habitat type of Pinus mercusii [1]. The West Block Batang Toru natural 1,890 ha with an altitude of 1700 mdpl and environmental factors such as air humidity of 73 to 91% with sunlight intensity ranging from 120 to 312 Candela. The West Block Batang Toru Forest area has a forest area of approximately 76,000 ha and the research location is an area that includes lowland to highland forest with an altitude of 669 to 1,875 masl. This is in accordance with the opinion of [6], who stated that the Zingiberaceae tribe can live at an altitude of more than 2000 meters above sea level so that the location of this study supports the growth of Zingiberaceae. The research area has environmental factors that are suitable for Zingiberaceae growth, such as air humidity of 33% to 95% and high rainfall ranging from 3,500 to 5,000 mm per year. [4], suggested that the habitat favored by the Zingiberaceae tribe is generally in humid, slightly shaded places and some species live in slightly open forest areas with full sun.

Habitat
The types of Zingiberaceae are found in two types of habitats, namely teresterial and epiphyte.
The terrestrial habitat is found in two types of substrates, namely soil and stone. Epiphytic habitat found attached to trees In this study found 16 species with the most terrestrial habitats, namely (Alpinia hansenii, Alpinia scabra, Amomum centrocephalum, Amomum cerasinum, Amomum hastilabium, Amomum citrinum, Boesenbergia belalongensis, Conamomum xanthoplebium, Globba leuchanta, Globba patens, Globba pendula, Hornstedtia leonurus, Hornstedtia tomentosa, Zingiber puberulum). The Meistera type of gyrolophos is found growing at ground level and attached to rocks, some individuals of this type are found above ground level. In the epiphytic habitat or attached to trees found two types, namely Camptandra sp. and Globba multifolia. Zingiberaceae is found at altitudes of 600 to 800 masl. The Zingiberaceae type is also found in forest peripheries as well as open areas with full sunlight (Figure 1). Most types of Zingiberaceae are found in forests, one type is found in forest periphery (Etlingera coccinea).

Rhizomes
The position of rhizomes of the types of Zingiberaceae can be distinguished into two groups, namely types with rhizomes above ground level with root stilts. (supporting roots) and rhizomes below ground level ( Figure 2). The types that have rhizomes above ground level are Amomum centrocephalum, Amomum citrinum and Hornstedtia tomentosa, while other types have rhizomes below ground level Figure 2 The position of the rhizome; rhizomes below ground level in Conamomum xanthoplebium (A), rhizomes above ground level with root stilts on Amomum citrinum (B

Leaves
The leaves in the Zingiberaceae tribe have a single leaf type with varying leaf build, namely jorong, lanceolate and elongated. The shape of the jorong leaves is found in the Camptandra and Globba clans, an elongated shape in the Hornstedtia clan and lanceolate in the Conamomum xanthoplebium and Alpinia scabra types.

Inflorescence Type
Inflorescences of the tribe Zingiberaceae based on the place where the flower appears can be grouped into three, namely from the rhizome (radicalis) of the armpits of the leaves (axilaris) and from the tip of the stem (terminalis) ( Figure 5). Terminalis inflorescences are found in the types

Fruit
The shape of the fruit in the Zingiberaceae tribe as a whole is round. The surface of the fruit varies, in the type of Alpinia scabra and Amomum cerasinum the surface of the fruit is slippery.
The surface of the fruit in Amomum cerasinum kasap, there are lines on the surface and when the fruit is split it will look like it has space on the inside and the same as the surface of the fruit. on the Globba clan ( Figure 6) Figure 6 Fruit form in the Zingiberaceae tribe; Round shape with a slippery fruit surface on Alpinia scabra (A), a round shape with a fruit surface has stripes and has space on the inside of the Amomum cerasinum (B), a round shape with three Globba pendula (C)

Ecology of Zingiberaceae
The types of Zingiberaceae generally occupy habitats that vary from a height of 669 to 1010 meters above sea level with air humidity ranging from 86 to 99%, the intensity of sunlight ranges from 125 to 78 Candela and rainfall ranges from 3500 to 4000 mm / year. The habitat occupied by the Zingiberaceae tribe starts from within the forest, forest periphery and open areas with full sunlight. In general, the types of Zingiberaceae are found to occupy the area around the river flow, while the relatively dry area is occupied by Etlingera coccinea. This is in accordance with the opinion of [7], who stated that the Etlingera clan grows clustered in places, secondary forests and open forests.
The diversity and abundance of the types of Zingiberaceae is affected by environmental conditions such as altitude, air temperature, light intensity, and air humidity. Zingiberaceae ecological data in Batang Toru Blok forest area West shows air temperature ranging from 21 to 23°C, humidity ranges from 84°C up to 99%, the pH of the soil ranges from 6 to 6.7, the light intensity ranges from 125 to 578 Candela. From the results of the study, it can be stated that the condition of the research site is classified as moist with the pH of the soil appropriate for growth and spread of Zingiberaceae plants. It is related to [8], who posits that the temperature range is allows optimum ginger growth is 25 to 30ºC. Temperature above 35 ºC will make the leaves dry out, while the lower the temperature then the age .The plant will get longer. Ginger plants can grow at a soil acidity (pH) of 4.3 to 7.4, but the optimum pH for ginger is 6.8 to 7.0 [9] Rainfall at the research station is about 3500 to 5000 mm/year. The number of types of Zingiberaceae scattered in this location is suspected to be one of them. because it has rainfall suitable for the growth of the Zingiberaceae type. This is in accordance with the opinion of [9], who stated that the area with an annual rainfall amount of 2500 to 4000 mm with the moon Wet 7 to 9 months is good for the growth of the Zingiberaceae tribe.  Habitat and Ecology: Large plants on the outskirts of forests and around river grooves at an altitude of 809 meters above sea level.