Bamboo harvesting in Vietnam — From variety selection to processing and preservation

Tre thuoc ho Hoa thao (Poaceae), phan ho Bambusoideae. Viet Nam co hon 200 loai tre, trong do pho bien nhat la tre gia (Bambusa bambos), luong (Dendrocalamus barbatus), nua (Neohouzeaua dullooa), may (Bambusa nutans) va truc (Phyllostachys). Tre la loai co khong lo, co the cao den 20-30 m voi duong kinh than 8-15 cm. Tre phat trien tu than ngam (re) va moi nam moc them mang moi.

Each type of bamboo has different characteristics. Bambusa bambos is hard and thick, suitable for construction and making interior furniture. Dendrocalamus barbatus has a large stem, used for house posts, partitions. Phyllostachys is slender, flexible, suitable for making handicrafts, bright, clear. Neohouzeaua is small, flexible, used for mats, baskets. Determine the purpose before harvesting to choose the right type.

Tre truong thanh (3-5 nam tuoi) la tot nhat de thu hoach. Dau hieu nhan biet: vo than co mau xanh dam hoac xanh vang, lop phan trang (silica) phu ben ngoai da phai, mat cat than cung va dac, la nho va it hon tre non. Tre 1-2 nam tuoi mau xanh tuoi, than mem, con bao la — khong nen chat. Tre tren 6 nam bat dau muc tu ben trong.

Harvest bamboo shoots in the dry season (October-February in the North, December-April in the South) when water content and starch levels in the shoots are lowest. Bamboo shoots harvested in the rainy season contain a lot of water and sugar, making them susceptible to insects and mold. According to tradition, Vietnamese farmers harvest bamboo shoots on the last days of the waning moon, when shoots have the least sap. Scientific research confirms that starch content decreases in the dry season.

Chuan bi dao phay hoac cua tay sac. Dao phay truyen thong cua Viet Nam (dao rua) la cong cu ly tuong — luoi nang va sac, co the chat than tre mot nhat. Can them day thung hoac xe keo de van chuyen. Deo gang tay bao ho vi vo tre co nhieu silica, de gay tray xuoc va nhiem trung.

Stake at a position on the upper surface of the first mound, 15-30 cm above ground level. Stake at a 45-degree angle so rainwater does not accumulate in the remaining corner (causing corner rot). Do not stake close to the ground as it will cause root rot and damage the root system below. When the tree begins to lean, gently push it back with your hand toward the side without people. Trees grow very quickly and heavily — always keep them on the safe side.

Sau khi ha cay, tia sach tat ca canh nhanh va la. Bat dau tu goc, dung dao phay chat sat than chinh. Cac mat nut thuong co canh moc ra — cat sach nhung khong khoet vao than. Giu lai canh lon neu can dung cho muc dich khac. La tre co the phoi kho lam tra (tra truc diep) hoac lam phan bon huu co.

Cat than tre thanh cac doan theo kich thuoc mong muon. Luon cat o vi tri giua hai mat nut, cach nut it nhat 5 cm. Mat nut la phan cung nhat cua tre, giup ngan nuoc va con trung xam nhap qua dau cat. Dung cua tay de co mat cat phang. Neu cat bang dao phay, chat tu hai phia de tranh tach than.

Ngam tre trong nuoc ngot (ao, ho, song) tu 4-8 tuan. Nuoc hoa tan tinh bot va duong trong than tre, loai bo nguon thuc an cua mot va nam. Dat da hoac vat nang len tren de tre khong noi. Thay nuoc moi 1-2 tuan neu co the. Day la phuong phap xu ly truyen thong, don gian va khong dung hoa chat.

Hun khoi la phuong phap xu ly tre truyen thong cua Viet Nam. Dat tre phia tren bep lua hoac lo hun va duy tri khoi am trong 2-4 tuan. Khoi chua cac hop chat phenol va creosote co tac dung diet nam moc va xua duoi con trung. Tre sau hun khoi co mau vang nau dep va mui thom dac trung. Dung cui kho, tranh cui uot tao qua nhieu nhiet truc tiep.

Sau khi xu ly, dung tre thang dung hoac ke nghieng 60-70 do trong bong mat co gio thong thoang. Khong phoi truc tiep duoi nang gay gat vi tre se nut. Tre can 4-8 tuan de kho hoan toan, tuy thuoc vao do day va khi hau. Do am ly tuong cua tre thanh pham la 12-15%. Xoay tre moi 2-3 ngay de kho deu.

Tre kho tot co mau xanh vang hoac vang nau deu, khong co vet nam den hoac lo moi. Go nhe vao than — tre kho phat ra tieng trong, giong va canh. Tre con am phat ra tieng duc. Kiem tra hai dau cat xem co vet nut doc than khong. Tre nut nghiem trong khong su dung duoc cho xay dung nhung van dung duoc cho do thu cong nho.

Bao quan tre o noi kho rao, thoang mat, cach mat dat it nhat 30 cm (ke tren gia do hoac pallet go). Tranh de truc tiep tren nen dat am vi tre se hut am va bi moc. Xep tre theo loai va kich thuoc, danh so de de quan ly. Tre xu ly tot co the bao quan 5-10 nam ma khong bi hu hai. Kiem tra dinh ky moi 2-3 thang de phat hien som dau hieu moi mot.