Analysis of the role of plant canopy on hydrological systems

High rainfall intensity causing high erosion rates in Indonesia. Land cover conditions greatly determine water degradation in the hydrological cycle. The shape and type of plants canopy have significant effect on soil structure and water absorption. This study aimed to examine the role of plant canopy on the value of rainwater canopy escape as a supporter of hydrological cycle. Tree species were determined based on the level of dominance at study site using transect method. The dominant trees are Sea Sengon Tree (Paraserianthes falcataria), Teak Tree (Tectona grandis), Suren Tree (Toona sinensis) and Durian Tree (Durio zibethinus). The results showed that high rainfall intensity with a long rain period affected the amount of canopy escape. Durian Tree has highest canopy density with value of 0.301, and Sengon Laut is the lowest with value of 0.240. The value of passing the canopy of the Suren Tree is lower than the other tree species. The shape of canopy of Suren tree, which is round and oval, also affects the lower pass value of canopy compared to other tree species. The higher the value of canopy density can reduce the value of canopy escape to support the hydrological cycle.

Drying a Standing Teak Tree using a Solar Kiln Drying Method

Understanding the rate of drying of standing trees dried by using a solar kiln drying method could help in predicting the change of moisture content in the tree over a period of drying time. The purpose of this study was to observe the change of moisture content profile in a standing tree during drying. A standing Tectona grandis tree was selected for the experiment with a diameter at breast height of 29 cm in a mixed-species plantation. The tree was girdled with 20 cm width at 20cm above ground. For the experiment, the tree was wrapped in a transparent plastic sheet and a black plastic sheet was installed at the bottom with an angle of 39 °C facing Southwest to maximize solar radiation, with the method being modified from the solar kiln method, which is known as a greenhouse type, with 2 layers of plastic cover. The black and white sheets were placed on the inner side for insulation and for collecting heat from the sun’s radiation, while the outer layer was transparent, which allowed radiation to propagate unhindered in the black sheet. In this study, a sensor for temperature and relative humidity (DHT22) was attached inside the wrapped plastic and the data recorded every 6 min. The results showed that drying a standing teak tree from an initial average moisture content of 105 % to a constant point of 60 % took 80 days under the maximum of the collected temperature of 46 °C inside the wrapped plastic; this finding confirmed that the predicted model of recharge and discharge curve was likely accurate.

Nilai Karakter dalam Karya Seni Batik Ngawi Sebagai Muatan Pendidikan Seni Rupa di Sekolah Dasar

The purpose of this study was to describe the character values in the batik art work with Ngawi's distinctive historical and natural motifs as a content of art education in elementary schools. This study uses a descriptive qualitative research method with a hermeneutic approach. The subjects in the study were Ngawi batik craftsmen. The data collection techniques used were interviews, observation, and documentation of the batik craftsmen and the resulting batik motifs. The data analysis technique used the interactive model analysis technique of Miles and Huberman. The results showed that the character values contained in the phytecanthropus erectus motif were religious, hard work, creative, love for the country, and communicative. The character values contained in the teak tree motif were religious, tolerance, discipline, hard work, creative, independent, communicative, peace-loving, and responsibility. The character values contained in the rice plant motif were religious, disciplined, hard work, national spirit, love for the country, respect for achievement, and communicative.

First report of Euschistus heros (Hemiptera: Pentatomidae) damaging teak trees (Tectona grandis) in the neotropics

Teak, Tectona grandis is one of the most valuable woods in the world. In Brazil, it is attacked by sap-sucking insects such as Euschistus heros, known as Neotropical brown stink bug. Here we report the first occurrence of this pest in teak tree plantations in Cáceres, Mato Grosso, Brazil. The injuries on the trees were characterized and photographed, along with the insects collected on plants. Injuries caused the apical bud to dry, advancing to the entire plant drying. Injuries occur from the histological damage caused by insect stylets and the toxic enzyme released into plant cells.

Understory Limits Surface Runoff and Soil Loss in Teak Tree Plantations of Northern Lao PDR

Many mountainous regions of the humid tropics experience serious soil erosion following rapid changes in land use. In northern Lao People’s Democratic Republic (PDR), the replacement of traditional crops by tree plantations, such as teak trees, has led to a dramatic increase in floods and soil loss and to the degradation of basic soil ecosystem services such as water filtration by soil, fertility maintenance, etc. In this study, we hypothesized that conserving understory under teak trees would protect soil, limit surface runoff, and help reduce soil erosion. Using 1 m2 microplots installed in four teak tree plantations in northern Lao PDR over the rainy season of 2017, this study aimed to: (1) assess the effects on surface runoff and soil loss of four understory management practices, namely teak with no understory (TNU; control treatment), teak with low density of understory (TLU), teak with high density of understory (THU), and teak with broom grass, Thysanolaena latifolia (TBG); (2) suggest soil erosion mitigation management practices; and (3) identify a field visual indicator allowing a rapid appraisal of soil erosion intensity. We monitored surface runoff and soil loss, and measured teak tree and understory characteristics (height and percentage of cover) and soil surface features. We estimated the relationships among these variables through statistics and regression analyses. THU and TBG had the smallest runoff coefficient (23% for both) and soil loss (465 and 381 g·m−2, respectively). The runoff coefficient and soil loss in TLU were 35% and 1115 g·m−2, respectively. TNU had the highest runoff coefficient and soil loss (60%, 5455 g·m−2) associated to the highest crusting rate (82%). Hence, the soil loss in TBG was 14-times less than in TNU and teak tree plantation owners could divide soil loss by 14 by keeping understory, such as broom grass, within teak tree plantations. Indeed, a high runoff coefficient and soil loss in TNU was explained by the kinetic energy of rain drops falling from the broad leaves of the tall teak trees down to bare soil, devoid of plant residues, thus leading to severe soil surface crusting and soil detachment. The areal percentage of pedestal features was a reliable indicator of soil erosion intensity. Overall, promoting understory, such as broom grass, in teak tree plantations would: (1) limit surface runoff and improve soil infiltrability, thus increase soil water stock available for both root absorption and groundwater recharge; and (2) mitigate soil loss while favoring soil fertility conservation.

Properties of Included Phloem in Teakwood

In some areas of Indonesia, the heartwood of teak tree (Tectona grandis L.f.) contains included phloem, which is categorized as defects. This paper characterized the colour and chemical properties of such abnormal wood. Three selected trees from Perhutani plantation, Randublatung region, were assessed. The heartwood colour properties were measured by CIELAB system. Result showed that the included phloem-containing heartwood (IPHW) was darker (L*), but less red (a*) and yellow (b*) compared to the adjacent normal heartwood (NHW). The lignin and ash contents were not significantly different in the wood radial direction. In contrast, the level of extractive contents were significantly different between sapwood and heartwood. The amount of ethanol-benzene extractive and solubility in 1% NaOH in the IPHW region were significantly higher than that in normal tissues. The analysis of extractive components using gas chromatography-mass spectrometry showed that the deoxylapachol and lapachol was highly marked in the IPWH region. The obtained results suggest that napthaquinone compounds were related to the protection against wood-destroying organisme attack.

Understorey vegetation drives surface runoff and soil loss in teak plantation-based system of Northern Laos

<p>Humid tropical mountainous area experiences serious soil erosion due to rapid changes in landuse, sometimes implying erosion prone management practices. In this study, we hypothesized that keeping understorey in teak tree plantation would protect soil and avoid soil erosion. We assessed the effects of 4 management practices in teak tree plantation area on water and soil losses using 6 replicated 1-m<sup>2</sup> microplots in four plantations situated in Northern Laos during the wet season of 2017. The landuses in the four plantations were teak without understorey (TNU), teak with low density of understorey (TLU), teak with high density of understorey (THU), and teak with broom grass, <em>Thysanolaena latifolia</em> (TBG). During the wet season of 2017, we monitored surface runoff and soil loss for 22 rainfall events. We also measured some of the teak tree and understorey characteristics (i.e. height and percentage of cover) and the percentage areas of soil surface features (i.e. litter, free aggregates, crusting, etc.). Relationships among these variables was estimated through multiple statistics and regression analyses. We found that runoff coefficient and soil loss were the smallest for THU and TBG: runoff coefficient was 23% for both treatments, and soil losses were 465 and 381 g m<sup>-2</sup>, respectively. Runoff coefficient and soil loss for TLU were 35% and 1115 g m<sup>-2</sup>, respectively. We observed the highest runoff coefficient and soil loss under TNU (60%, 5455 g m<sup>-2</sup>) associated to the highest crusting rate (82%). High runoff coefficient and soil loss under TNU was explained by the kinetic energy of rain drops falling from the broad leaves of the tall teak trees down to bare soil, devoid of plant residues, thus leading to severe soil surface crusting and detachment. Overall, promoting understorey such as broom grass in teak tree plantations would (1) limit surface runoff and improve soil infiltrability, thus increase the soil water stock available for both root absorption and groundwater recharge, and (2) mitigate soil loss and favour soil fertility conservation.</p>

Effectiveness Teston Hardness Performance of Plastic Waste and Sawdust Composite

The strength of a material is one option used to determine the use of forms. The use of plastics on product packaging is an efficient choice because plastics is light, practical and easy to forms. This study is done to measure the plastic waste hardness of mixed HDPE and PET type with teak tree sawdust which melted into two portions by the amount of 18 gram. This study finds the highest hardness index was achieved by the mixture of 1.5 gram of sawdust, 5 gram PET and 11.5 gram HDPE with the hardnesss point of 131. 3 N/mm under the 5000 gram pressure and temperatureof 100°C while the lowest point of 86.6 N/mm by the mixture of 1 gram sawdust, 625 gram PET and 10.7 gram HDPE under the 5000 gram pressure and temperature of 100°C. It can be seen that the lower the temperature of the mixture compositions, the better the hardness because the mixture is merged and binded better