Hevea brasiliensis Muell. Arg. is an important industrial crop for natural rubber production. Latex biosynthesis occurs in the cytoplasm of highly specialized latex cells and latex bleeds out when the bark is tapped. ...Hevea brasiliensis Muell. Arg. is an important industrial crop for natural rubber production. Latex biosynthesis occurs in the cytoplasm of highly specialized latex cells and latex bleeds out when the bark is tapped. Ethylene stimulation acts by increasing latex flow to the cells of inner bark from the latex cells, increasing yield and may affect the physical properties of rubberwood. The aim of this work was to assess the permeability properties of ethylene treated rubberwood （TRW） relative to untreated rubberwood （URW）, because in wood industrial technology, permeability relates to bondability and wood preservative treatments. The Hevea samples were of PRIM 600 strain, from 20-25 years old rubber trees. The TRW rubber trees had been stimulated by ethylene gas for six years. The rubberwood specimens were collected at a single plot of plantation to minimize variations in soil fertility, environmental exposures and silvicultural treatments at Tumbon Chaibury, Amphor Chaibury, Suratthani Province, Thailand. The moisture contents （MC） of fresh rubberwood were significantly different （P 〈 0.05） at 75% for TRW and 64% for URW. The permeability experiment followed Darcy＇s law, and the hydrostatic pressure was controlled. The average 0.005 Darcy water permeability of TRW was significantly higher than the 0.001 Darcy for URW. Water absorptions during 4 h water immersion of rubberwood blocks differed significantly, and TRW had higher absorption than URW also across 6 d of immersion. Scanning electron microscope （SEM） imaging showed anatomical effects that contribute to the fivefold permeability increase.展开更多
In order to gain the drying characteristics of improved-preservative treated rubberwood, the 100℃ drying test method was used. Based on the test results, rubberwood drying schedules for lab test were made out. Then a...In order to gain the drying characteristics of improved-preservative treated rubberwood, the 100℃ drying test method was used. Based on the test results, rubberwood drying schedules for lab test were made out. Then a series of lab experiments were conducted in a wood drying trial machine, and finally 3 optimized drying schedules for improved-preservative treated rubberwood were gained. And a series of follow-up pilot tests were executed in a rubber wood mill in Hainan province. Results showed that rubberwood with or without pith should be dried separately. Pith free rubberwood could be dried according to the high temperature Schedule C with good drying quality. Uniform spacing stickers and heavy load on top of stack was recommended to reduce deformation. In order to keep the original color of rubberwood, the rubberwood should be dried according to Schedule A. And Schedule B can also be adopted according to the requirement of final products of the rubberwood By the manufactory.展开更多
The biological characteristics of the insects and fungi which seriously attack rubberwood and the present state of rubberwood biodeterioration in China were described. The fungi attaching rubberwood consist mainly of ...The biological characteristics of the insects and fungi which seriously attack rubberwood and the present state of rubberwood biodeterioration in China were described. The fungi attaching rubberwood consist mainly of blue stain fungi, moulds and rotting fungi. The insects include beetle borers, termites and some other Coleopteran species, such as longicorns and snout beetles etc., the total insect species are near to one hundred. The stain fungi, moulds and beetles should be paid more attention to in rubberwood preservation.展开更多
文摘Hevea brasiliensis Muell. Arg. is an important industrial crop for natural rubber production. Latex biosynthesis occurs in the cytoplasm of highly specialized latex cells and latex bleeds out when the bark is tapped. Ethylene stimulation acts by increasing latex flow to the cells of inner bark from the latex cells, increasing yield and may affect the physical properties of rubberwood. The aim of this work was to assess the permeability properties of ethylene treated rubberwood （TRW） relative to untreated rubberwood （URW）, because in wood industrial technology, permeability relates to bondability and wood preservative treatments. The Hevea samples were of PRIM 600 strain, from 20-25 years old rubber trees. The TRW rubber trees had been stimulated by ethylene gas for six years. The rubberwood specimens were collected at a single plot of plantation to minimize variations in soil fertility, environmental exposures and silvicultural treatments at Tumbon Chaibury, Amphor Chaibury, Suratthani Province, Thailand. The moisture contents （MC） of fresh rubberwood were significantly different （P 〈 0.05） at 75% for TRW and 64% for URW. The permeability experiment followed Darcy＇s law, and the hydrostatic pressure was controlled. The average 0.005 Darcy water permeability of TRW was significantly higher than the 0.001 Darcy for URW. Water absorptions during 4 h water immersion of rubberwood blocks differed significantly, and TRW had higher absorption than URW also across 6 d of immersion. Scanning electron microscope （SEM） imaging showed anatomical effects that contribute to the fivefold permeability increase.
文摘In order to gain the drying characteristics of improved-preservative treated rubberwood, the 100℃ drying test method was used. Based on the test results, rubberwood drying schedules for lab test were made out. Then a series of lab experiments were conducted in a wood drying trial machine, and finally 3 optimized drying schedules for improved-preservative treated rubberwood were gained. And a series of follow-up pilot tests were executed in a rubber wood mill in Hainan province. Results showed that rubberwood with or without pith should be dried separately. Pith free rubberwood could be dried according to the high temperature Schedule C with good drying quality. Uniform spacing stickers and heavy load on top of stack was recommended to reduce deformation. In order to keep the original color of rubberwood, the rubberwood should be dried according to Schedule A. And Schedule B can also be adopted according to the requirement of final products of the rubberwood By the manufactory.
文摘The biological characteristics of the insects and fungi which seriously attack rubberwood and the present state of rubberwood biodeterioration in China were described. The fungi attaching rubberwood consist mainly of blue stain fungi, moulds and rotting fungi. The insects include beetle borers, termites and some other Coleopteran species, such as longicorns and snout beetles etc., the total insect species are near to one hundred. The stain fungi, moulds and beetles should be paid more attention to in rubberwood preservation.
