{"id":8591,"date":"2009-03-24T02:22:12","date_gmt":"2009-03-23T19:22:12","guid":{"rendered":"http:\/\/vafs.gov.vn\/vn\/2009\/03\/buoc-dau-nghien-cuu-ve-khuyet-tat-tu-nhien-go-hong\/"},"modified":"2019-09-25T10:18:28","modified_gmt":"2019-09-25T03:18:28","slug":"buoc-dau-nghien-cuu-ve-khuyet-tat-tu-nhien-go-hong","status":"publish","type":"post","link":"https:\/\/vafs.gov.vn\/vn\/buoc-dau-nghien-cuu-ve-khuyet-tat-tu-nhien-go-hong\/","title":{"rendered":"B\u01b0\u1edbc \u0111\u1ea7u nghi\u00ean c\u1ee9u v\u1ec1 khuy\u1ebft t\u1eadt t\u1ef1 nhi\u00ean g\u1ed7 H\u00f4ng"},"content":{"rendered":"

Nguy\u1ec5n T\u1eed Kim<\/em><\/strong><\/p>\n

Vi\u1ec7n khoa h\u1ecdc L\u00e2m nghi\u1ec7p Vi\u1ec7t Nam<\/em><\/p>\n

C\u00e2y H\u00f4ng ( Paulownia fortunei<\/em> Hemsl) thu\u1ed9c h\u1ecd Hoa m\u00f5m ch\u00f3 (Scrophulariaceae<\/em>), l\u00e0 c\u00e2y g\u1ed7 l\u1edbn, cao 20-30m, \u0111\u01b0\u1eddng k\u00ednh 50-60cm th\u1eadm ch\u00ed c\u00f3 c\u00e2y \u0111\u01b0\u1eddng k\u00ednh tr\u00ean 100 cm. C\u00e2y \u1edf tu\u1ed5i 10 c\u00f3 th\u1ec3 \u0111\u1ea1t th\u1ec3 t\u00edch 0,4-0,5 m3<\/sup>. Ph\u00e2n b\u1ed1 ch\u1ee7 y\u1ebfu \u1edf Trung Qu\u1ed1c, Vi\u1ec7t Namv\u00e0 L\u00e0o. \u1edf Vi\u1ec7t Nam, c\u00e2y H\u00f4ng c\u00f3 m\u1eb7t \u1edf c\u00e1c v\u00f9ng B\u1eafc Trung b\u1ed9, T\u00e2y B\u1eafc, Trung t\u00e2m, \u0110\u00f4ng B\u1eafc b\u1ed9, n\u01a1i c\u00f3 \u0111\u1ed9 cao 300-1300m, l\u01b0\u1ee3ng m\u01b0a 1500-1850mm, nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh n\u0103m 20-230<\/sup>C. Trong t\u1ef1 nhi\u00ean c\u00e2y H\u00f4ng xu\u1ea5t hi\u1ec7n \u1edf n\u01a1i \u0111\u1ea5t tr\u1ed1ng ho\u1eb7c m\u1ecdc xen v\u1edbi c\u00e1c lo\u00e0i c\u00e2y \u01b0a s\u00e1ng kh\u00e1c v\u00e0 th\u01b0\u1eddng chi\u1ebfm t\u1ea7ng tr\u00ean c\u1ee7a r\u1eebng. C\u00e2y H\u00f4ng t\u00e1i sinh ch\u1ed3i m\u1ea1nh, ngo\u00e0i ra c\u00f2n t\u00e1i sinh t\u1eeb r\u1ec5 th\u00e0nh c\u00e2y m\u1edbi khi b\u1ecb t\u00e1c \u0111\u1ed9ng c\u01a1 gi\u1edbi. Hi\u1ec7n nay, c\u00e2y H\u00f4ng \u0111\u00e3 \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn \u0111\u01b0a v\u00e0o danh s\u00e1ch c\u00e1c lo\u00e0i c\u00e2y tr\u1ed3ng r\u1eebng trong d\u1ef1 \u00e1n tr\u1ed3ng m\u1edbi 5 tri\u1ec7u ha r\u1eebng c\u1ee7a Vi\u1ec7t Nam.<\/p>\n

C\u00e2y H\u00f4ng \u0111\u00e3 \u0111\u01b0\u1ee3c nhi\u1ec1u n\u01b0\u1edbc nh\u01b0 Trung Qu\u1ed1c, \u0110\u00e0i Loan, M\u1ef9, \u00fac,\u2026 quan t\u00e2m nghi\u00ean c\u1ee9u v\u1ec1 ph\u00e2n lo\u1ea1i, c\u00e1c bi\u1ec7n ph\u00e1p k\u1ef9 thu\u1eadt kinh doanh (g\u00e2y tr\u1ed3ng, ch\u0103m s\u00f3c, khai th\u00e1c), c\u00e1c thu\u1ed9c t\u00ednh c\u1ee7a g\u1ed7, k\u1ef9 thu\u1eadt ch\u1ebf bi\u1ebfn, k\u1ef9 thu\u1eadt b\u1ea3o qu\u1ea3n . . . G\u1ed7 H\u00f4ng c\u00f3 m\u00e0u tr\u1eafng v\u00e0ng, m\u1ecbn, m\u1ec1m nh\u1eb9, kh\u00f4ng b\u1ecb n\u1ee9t n\u1ebb, c\u00e1ch nhi\u1ec7t t\u1ed1t, c\u00f3 kh\u1ea3 n\u0103ng ch\u1ed1ng m\u1ecdt, m\u1ee5c, d\u1ec5 hong s\u1ea5y v\u00e0 gia c\u00f4ng ch\u1ebf bi\u1ebfn; l\u00e0 lo\u1ea1i g\u1ed7 c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng cho nhi\u1ec1u m\u1ee5c \u0111\u00edch kh\u00e1c nhau nh\u01b0 g\u1ed7 x\u00e2y d\u1ef1ng, ch\u1ebf bi\u1ebfn b\u1ed9t gi\u1ea5y, \u0111\u00f3ng \u0111\u1ed3 gia d\u1ee5ng, bao b\u00ec, n\u00f4ng c\u1ee5, h\u00e0ng th\u1ee7 c\u00f4ng m\u1ef9 ngh\u1ec7. G\u1ed7 H\u00f4ng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng kh\u00e1 ph\u1ed5 bi\u1ebfn \u1edf Trung Qu\u1ed1c nh\u01b0ng \u1edf Vi\u1ec7t Namth\u00ec ch\u01b0a \u0111\u01b0\u1ee3c \u01b0a chu\u1ed9ng. Vi\u1ec7c thi\u1ebfu hi\u1ec3u bi\u1ebft v\u1ec1 lo\u1ea1i g\u1ed7 n\u00e0y l\u00e0 m\u1ed9t nguy\u00ean nh\u00e2n d\u1eabn \u0111\u1ebfn \u00edt s\u1eed d\u1ee5ng n\u00f3. Nghi\u00ean c\u1ee9u v\u1ec1 khuy\u1ebft t\u1eadt g\u1ed7 s\u1ebd g\u00f3p ph\u1ea7n \u0111\u00e1nh gi\u00e1 \u0111\u01b0\u1ee3c kh\u1ea3 n\u0103ng l\u1ee3i d\u1ee5ng g\u1ed7 c\u1ee7a lo\u00e0i c\u00e2y n\u00e0y.<\/p>\n

I. V\u1eadt li\u1ec7u v\u00e0 ph\u01b0\u01a1ng ph\u00e1p nghi\u00ean c\u1ee9u<\/h2>\n

Nghi\u00ean c\u1ee9u n\u00e0y nh\u1eb1m t\u00ecm hi\u1ec3u \u0111\u1eb7c \u0111i\u1ec3m v\u00e0 khuy\u1ebft \u0111i\u1ec3m k\u1ef9 thu\u1eadt c\u1ee7a g\u1ed7, t\u01b0\u01a1ng quan gi\u1eefa nh\u1eefng bi\u1ec3u hi\u1ec7n th\u1ea5y \u0111\u01b0\u1ee3c tr\u00ean v\u1ecf v\u00e0 khuy\u1ebft \u0111i\u1ec3m b\u00ean trong g\u1ed7.<\/p>\n

Ti\u1ebfn h\u00e0nh ch\u1ecdn r\u1eebng, ch\u1ecdn c\u00e2y, c\u01b0a kh\u00fac v\u00e0 l\u1ea5y m\u1eabu nghi\u00ean c\u1ee9u theo \u0111\u00fang y\u00eau c\u1ea7u trong TCVN 355-70 v\u00e0 356-70. C\u00e1c c\u00e2y \u0111\u01b0\u1ee3c ch\u1ecdn n\u1eb1m trong m\u1ed9t khu v\u1ef1c c\u00f3 c\u00f9ng \u0111i\u1ec1u ki\u1ec7n s\u1ed1ng nh\u01b0 h\u01b0\u1edbng ph\u01a1i, l\u1eadp \u0111\u1ecba, t\u1ed5 th\u00e0nh. M\u1eabu v\u1eadt nghi\u00ean c\u1ee9u \u0111\u01b0\u1ee3c l\u1ea5y t\u1ea1i L\u00e2m tr\u01b0\u1eddng Ng\u00e2n S\u01a1n, huy\u1ec7n Ng\u00e2n S\u01a1n, t\u1ec9nh B\u1eafc K\u1ea1n; h\u01b0\u1edbng ph\u01a1i \u0111\u00f4ng nam, \u0111\u1ed9 d\u1ed1c 15-170<\/sup>, \u0111\u1ea5t feralit ph\u00e1t tri\u1ec3n tr\u00ean phi\u1ebfn th\u1ea1ch s\u00e9t, t\u1ea7ng d\u1ea7y g\u1ea7n su\u1ed1i, c\u00f3 \u0111\u1ed9 \u1ea9m cao. Vi\u1ec7c nghi\u00ean c\u1ee9u khuy\u1ebft t\u1eadt b\u00ean ngo\u00e0i \u0111\u01b0\u1ee3c ti\u1ebfn h\u00e0nh \u1edf ph\u1ea7n th\u00e2n th\u1eb3ng d\u01b0\u1edbi c\u00e0nh. Tr\u01b0\u1edbc khi ch\u1eb7t m\u00f4 t\u1ea3 v\u1eafn t\u1eaft \u0111\u1eb7c \u0111i\u1ec3m h\u00ecnh th\u00e1i, t\u00ecnh h\u00ecnh sinh tr\u01b0\u1edfng v\u00e0 \u0111\u00e1nh d\u1ea5u h\u01b0\u1edbng \u0111\u00f4ng-t\u00e2y-nam-b\u1eafc b\u1eb1ng b\u00fat s\u01a1n l\u00ean th\u00e2n c\u00e2y \u0111\u01b0\u1ee3c ch\u1ecdn. Sau khi ch\u1eb7t h\u1ea1 ph\u1ea7n th\u00e2n d\u01b0\u1edbi c\u00e0nh ti\u1ebfn h\u00e0nh quan s\u00e1t v\u00e0 ghi ch\u00e9p nh\u1eefng bi\u1ec3u hi\u1ec7n b\u00ean ngo\u00e0i nh\u01b0 \u0111\u1ed9 d\u00e0i d\u01b0\u1edbi c\u00e0nh, \u0111\u01b0\u1eddng k\u00ednh g\u1ed1c, \u0111\u01b0\u1eddng k\u00ednh ng\u1ecdn, \u0111\u01b0\u1eddng k\u00ednh l\u00f5i, \u0111\u1ed9 cong… sau \u0111\u00f3 xem x\u00e9t, \u0111o \u0111\u1ebfm, x\u00e1c \u0111\u1ecbnh v\u1ecb tr\u00ed c\u1ee7a c\u00e1c bi\u1ec3u hi\u1ec7n b\u1ea5t th\u01b0\u1eddng tr\u00ean v\u1ecf c\u00e2y theo c\u00e1c h\u01b0\u1edbng v\u00e0 \u0111\u1ed9 cao. Sau khi nghi\u00ean c\u1ee9u \u0111\u1ea7y \u0111\u1ee7 c\u00e1c bi\u1ec3u hi\u1ec7n b\u00ean ngo\u00e0i, ph\u1ea7n th\u00e2n n\u00e0y \u0111\u01b0\u1ee3c \u0111em x\u1ebb th\u00e0nh v\u00e1n v\u00e0 nghi\u00ean c\u1ee9u c\u00e1c khuy\u1ebft t\u1eadt g\u1ed7 t\u01b0\u01a1ng \u1ee9ng hay kh\u00f4ng t\u01b0\u01a1ng \u1ee9ng v\u1edbi nh\u1eefng bi\u1ec3u hi\u1ec7n tr\u00ean v\u1ecf. K\u00edch th\u01b0\u1edbc c\u1ee7a c\u00e1c khuy\u1ebft t\u1eadt t\u00ednh b\u1eb1ng cm v\u00e0 ch\u00ednh x\u00e1c t\u1edbi 0,1 cm.<\/p>\n

C\u00e1c k\u1ebft qu\u1ea3 nghi\u00ean c\u1ee9u \u0111\u01b0\u1ee3c ph\u00e2n t\u00edch, x\u1eed l\u00fd v\u00e0 \u0111\u00e1nh gi\u00e1 d\u1ef1a tr\u00ean l\u00fd thuy\u1ebft th\u1ed1ng k\u00ea sinh h\u1ecdc \u0111\u1ee7 \u0111\u1ed9 tin \u0111\u1ec3 t\u1eeb m\u1eabu \u0111i\u1ec3n h\u00ecnh \u0111i \u0111\u1ebfn k\u1ebft lu\u1eadn cho t\u1ed5ng th\u1ec3.<\/p>\n

II. K\u1ebft qu\u1ea3 nghi\u00ean c\u1ee9u v\u00e0 th\u1ea3o lu\u1eadn<\/h2>\n

1. Nh\u1eefng nh\u1eadn \u0111\u1ecbnh chung<\/strong><\/p>\n

Tr\u00ean c\u01a1 s\u1edf x\u00e1c \u0111\u1ecbnh chi\u1ec1u cao c\u00e2y, ph\u1ea7n th\u00e2n d\u01b0\u1edbi c\u00e0nh, ph\u1ea7n ng\u1ecdn, \u0111\u01b0\u1eddng k\u00ednh v\u00e0 v\u00f2ng sinh tr\u01b0\u1edfng c\u1ee7a c\u00e2y ch\u00fang t\u00f4i nh\u1eadn th\u1ea5y H\u00f4ng l\u00e0 lo\u00e0i c\u00e2y c\u00f3 n\u0103ng su\u1ea5t sinh tr\u01b0\u1edfng cao. T\u1ed1c \u0111\u1ed9 t\u0103ng tr\u01b0\u1edfng chi\u1ec1u cao t\u1eeb 1,6- 1,8m\/n\u0103m v\u00e0 \u0111\u01b0\u1eddng k\u00ednh t\u1eeb 2,3 – 2,7cm\/n\u0103m. S\u1ef1 ph\u00e1t tri\u1ec3n theo chi\u1ec1u cao v\u00e0 h\u00ecnh d\u00e1ng c\u00e2y tu\u1ef3 thu\u1ed9c v\u00e0o \u0111i\u1ec1u ki\u1ec7n sinh th\u00e1i, n\u1ebfu g\u1eb7p \u0111\u1ea5t t\u1ed1t, \u00e1nh s\u00e1ng \u0111\u1ea7y \u0111\u1ee7 th\u00ec sau 10 n\u0103m c\u00e2y cao kho\u1ea3ng 18-20 m v\u00e0 \u0111\u01b0\u1eddng k\u00ednh t\u1ea1i v\u1ecb tr\u00ed 1,3m l\u00e0 35-40cm. Nh\u1eefng c\u00e2y m\u1ecdc trong qu\u1ea7n th\u1ee5 c\u00f3 h\u00ecnh th\u00f9 v\u00e0 ph\u1ea9m ch\u1ea5t g\u1ed7 t\u1ed1t h\u01a1n c\u00e2y m\u1ecdc l\u1ebb tr\u00ean nh\u1eefng di\u1ec7n t\u00edch \u0111\u1ea5t tr\u1ed1ng. M\u1ed9t \u0111\u1eb7c \u0111i\u1ec3m \u0111\u1eb7c bi\u1ec7t c\u1ee7a g\u1ed7 H\u00f4ng l\u00e0 r\u1ed7ng ru\u1ed9t t\u1eeb g\u1ed1c t\u1edbi ng\u1ecdn v\u00e0 g\u1eb7p \u1edf t\u1ea5t c\u1ea3 c\u00e1c c\u00e2y v\u1edbi k\u00edch th\u01b0\u1edbc t\u1eeb 2-4cm; \u1edf \u0111\u00e2y r\u1ed7ng ru\u1ed9t kh\u00f4ng ph\u1ea3i do b\u1ecb s\u00e2u b\u1ec7nh ph\u00e1 h\u1ea1i m\u00e0 do tu\u1ef7 c\u00e2y. Tuy nhi\u00ean, m\u1ed9t s\u1ed1 c\u00e2y do b\u1ecb c\u1ea3 s\u00e2u n\u1ea5m ph\u00e1 h\u1ea1i n\u00ean r\u1ed7ng ru\u1ed9t l\u1edbn h\u01a1n v\u00e0 kh\u00f4ng c\u00f2n gi\u1eef \u0111\u01b0\u1ee3c d\u1ea1ng h\u00ecnh tr\u00f2n nguy\u00ean thu\u1ef7. Kh\u00f4ng g\u1eb7p tr\u01b0\u1eddng h\u1ee3p n\u00e0o c\u00e2y g\u1ed7 hai hay nhi\u1ec1u t\u00e2m.<\/p>\n

2. Khuy\u1ebft t\u1eadt g\u1ed7<\/strong><\/p>\n

2.1. Nh\u1eefng bi\u1ec3u hi\u1ec7n tr\u00ean v\u1ecf c\u1ee7a khuy\u1ebft t\u1eadt<\/em><\/strong>.<\/em><\/p>\n

+ Hoa h\u1ed3ng: l\u00e0 d\u1ea5u hi\u1ec7u b\u00ean ngo\u00e0i c\u1ee7a g\u1ed1c c\u00e0nh \u0111\u00e3 \u0111\u01b0\u1ee3c b\u1ecdc l\u1ea1i trong th\u00e2n g\u1ed7, c\u00f3 bi\u1ec3u hi\u1ec7n l\u00e0 nh\u1eefng \u0111\u01b0\u1eddng g\u1edd cong tr\u00ean v\u1ecf gi\u1ed1ng nh\u01b0 h\u00ecnh r\u00e2u m\u00e9p, d\u01b0\u1edbi ph\u1ea7n r\u00e2u m\u00e9p l\u00e0 ph\u1ea7n v\u1ecf b\u1ecb nh\u0103n nh\u00fam c\u00f3 qui lu\u1eadt. Khi b\u00f3c v\u1ecf t\u1ea1i v\u1ecb tr\u00ed hoa h\u1ed3ng th\u1ea5y ph\u1ea7n g\u1ed7 b\u00ean trong b\u1ecb u\u1ed1n xo\u1eafn. \u0110\u00e2y ch\u00ednh l\u00e0 l\u1edbp g\u1ed7 b\u1ecdc ph\u00e1t tri\u1ec3n ph\u1ee7 k\u00edn g\u1ed1c c\u00e0nh, \u0111\u01b0\u1eddng k\u00ednh th\u01b0\u1eddng g\u1eb7p \u1edf hoa h\u1ed3ng g\u1ed7 H\u00f4ng l\u00e0 2-3cm. Tu\u1ef3 theo k\u00edch th\u01b0\u1edbc c\u1ee7a hoa h\u1ed3ng ta c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c k\u00edch th\u01b0\u1edbc c\u1ee7a g\u1ed1c c\u00e0nh.<\/p>\n

+ B\u01b0\u1edbu: L\u00e0 bi\u1ec3u hi\u1ec7n n\u1ed5i c\u1ee5c b\u1ed9, s\u1ea7n s\u00f9i tr\u00ean v\u1ecf, che d\u1ea5u g\u1ed1c c\u00e0nh b\u00ean trong ho\u1eb7c m\u1ed9t t\u1ed5n th\u01b0\u01a1ng n\u00e0o \u0111\u00f3 tr\u00ean th\u00e2n g\u1ed7 \u0111\u00e3 \u0111\u01b0\u1ee3c l\u1edbp g\u1ed7 b\u1ecdc ph\u00e1t tri\u1ec3n ph\u1ee7 k\u00edn v\u00e0 do m\u1ed9t nguy\u00ean nh\u00e2n n\u00e0o \u0111\u00f3 ph\u1ea7n g\u1ed7 b\u1ecdc n\u00e0y ph\u00e1t tri\u1ec3n m\u1ea1nh h\u01a1n ph\u1ea7n g\u1ed7 b\u00ean c\u1ea1nh n\u00ean n\u1ed5i g\u1ed3 l\u00ean. \u1edf g\u1ed7 H\u00f4ng ph\u1ea7n th\u00e2n th\u1eb3ng d\u01b0\u1edbi c\u00e0nh \u00edt g\u1eb7p b\u01b0\u1edbu.<\/p>\n

+ C\u00e1c bi\u1ec3u hi\u1ec7n kh\u00f4ng b\u00ecnh th\u01b0\u1eddng kh\u00e1c tr\u00ean v\u1ecf: L\u00e0 nh\u1eefng bi\u1ec3u hi\u1ec7n nh\u01b0 n\u1ee9t, m\u1ea7u s\u1eabm, s\u00f9i nh\u1ef1a, c\u00f3 th\u1ec3 che d\u1ea5u m\u1ed9t khuy\u1ebft \u0111i\u1ec3m n\u00e0o \u0111\u00f3 trong g\u1ed7 ho\u1eb7c kh\u00f4ng. C\u00e1c khuy\u1ebft \u0111i\u1ec3m n\u00e0y c\u00f3 th\u1ec3 do t\u00e1c \u0111\u1ed9ng c\u01a1 gi\u1edbi, s\u00e2u b\u1ec7nh h\u1ea1i g\u00e2y ra. Qua \u0111i\u1ec1u tra th\u1ea5y c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng s\u00f9i nh\u1ef1a nh\u01b0ng t\u1ef7 l\u1ec7 s\u1ed1 c\u00e2y v\u00e0 s\u1ed1 ch\u1ed7 s\u00f9i nh\u1ef1a th\u1ea5p.<\/em> <\/strong><\/p>\n

2.2. C\u00e1c khuy\u1ebft t\u1eadt c\u1ee7a th\u00e2n c\u00e2y.<\/em> <\/strong><\/p>\n

+ Th\u00f3t ng\u1ecdn: L\u00e0 s\u1ef1 gi\u1ea3m d\u1ea7n c\u1ee7a \u0111\u01b0\u1eddng k\u00ednh g\u1ed7 tr\u00f2n theo chi\u1ec1u t\u1eeb g\u1ed1c t\u1edbi ng\u1ecdn kh\u00fac g\u1ed7. \u1edf ph\u1ea7n th\u00e2n d\u01b0\u1edbi c\u00e0nh c\u1ee7a g\u1ed7 H\u00f4ng, x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c \u0111\u1ed9 th\u00f3t ng\u1ecdn (\u0111\u1ed9 thon) \u00a1=”1,3cm\/m. + B\u1ea1nh: L\u00e0 ph\u1ea7n g\u1ed7 \u1edf g\u1ed1c v\u00e0 th\u00e2n g\u1ea7n g\u1ed1c ph\u00e1t tri\u1ec3n th\u00e0nh kh\u00eda (m\u00fai). K\u1ebft qu\u1ea3 \u0111i\u1ec1u tra cho th\u1ea5y c\u00e2y H\u00f4ng c\u00f3 b\u1ea1nh th\u1ea5p, kh\u00f4ng g\u1eb7p tr\u01b0\u1eddng h\u1ee3p n\u00e0o b\u1ea1nh cao tr\u00ean 50 cm.<\/p>\n

+ L\u1ec7ch t\u00e2m: \u0110a s\u1ed1 c\u00e1c c\u00e2y g\u1ed7 H\u00f4ng \u0111\u1ec1u l\u1ec7ch t\u00e2m nh\u01b0ng \u0111\u1ed9 l\u1ec7ch t\u00e2m kh\u00f4ng nhi\u1ec1u. \u0110\u1ed9 d\u1eb9t \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh T = 5,8%.<\/p>\n

+ Th\u00e2n cong: R\u1ea5t \u00edt g\u1eb7p \u1edf g\u1ed7 H\u00f4ng, n\u1ebfu c\u00f3 ch\u1ec9 l\u00e0 th\u00e2n cong m\u1ed9t chi\u1ec1u v\u00e0 \u0111\u1ed9 cong l\u00e0 kh\u00f4ng \u0111\u00e1ng k\u1ec3<\/p>\n

2.3. Khuy\u1ebft t\u1eadt m\u1eaft g\u1ed7.<\/em><\/strong><\/p>\n

M\u1eaft h\u00ecnh th\u00e0nh l\u00e0 do g\u1ed1c c\u00e0nh \u0111\u01b0\u1ee3c b\u1ecdc l\u1ea1i trong th\u00e2n g\u1ed7. M\u1eaft l\u00e0 khuy\u1ebft t\u1eadt c\u00f3 \u1ea3nh h\u01b0\u1edfng l\u1edbn \u0111\u1ebfn ch\u1ea5t l\u01b0\u1ee3ng v\u00e0 kh\u1ea3 n\u0103ng t\u1eadn d\u1ee5ng c\u1ee7a g\u1ed7. K\u1ebft qu\u1ea3 nghi\u00ean c\u1ee9u cho th\u1ea5y s\u1ed1 l\u01b0\u1ee3ng m\u1eaft \u1edf ph\u1ea7n th\u00e2n ph\u00eda d\u01b0\u1edbi t\u01b0\u01a1ng \u0111\u1ed1i \u00edt, c\u00e0ng l\u00ean cao c\u00e0ng t\u0103ng d\u1ea7n v\u00e0 kho\u1ea3ng t\u1eeb 6-8m tr\u1edf \u0111i th\u00ec h\u1ea7u nh\u01b0 kh\u00f4ng t\u0103ng n\u1eefa. S\u1ef1 ph\u00e2n b\u1ed1 c\u1ee7a m\u1eaft theo chi\u1ec1u cao tr\u00ean th\u00e2n c\u00e2y kh\u00f4ng \u0111\u1ec1u, n\u01a1i nhi\u1ec1u n\u01a1i \u00edt nh\u01b0ng t\u01b0\u01a1ng \u0111\u1ed1i \u0111\u1ec1u theo c\u00e1c h\u01b0\u1edbng. \u0110\u01b0\u1eddng k\u00ednh m\u1eaft v\u00e0 chi\u1ec1u d\u00e0i m\u1eaft tr\u00ean c\u00e1c c\u00e2y m\u1ecdc trong qu\u1ea7n th\u1ee5 nh\u1ecf h\u01a1n tr\u00ean c\u00e2y m\u1ecdc l\u1ebb ngo\u00e0i ch\u1ed7 tr\u1ed1ng (\u0111\u01b0\u1eddng k\u00ednh 1-2cm, d\u00e0i 4-4,5cm \u0111\u1ed1i v\u1edbi c\u00e2y m\u1ecdc trong qu\u1ea7n th\u1ee5 v\u00e0 \u0111\u01b0\u1eddng k\u00ednh 2-3cm, d\u00e0i 5-5,5cm \u0111\u1ed1i v\u1edbi c\u00e2y m\u1ecdc l\u1ebb). Chi\u1ec1u d\u00e0i v\u00e0 \u0111\u01b0\u1eddng k\u00ednh m\u1eaft t\u0103ng theo chi\u1ec1u cao c\u1ee7a c\u00e2y. T\u1ef7 l\u1ec7 \u0111o\u1ea1n m\u1eaft th\u1ed1i tr\u00ean to\u00e0n b\u1ed9 chi\u1ec1u d\u00e0i c\u1ee7a m\u1eaft chi\u1ebfm 15-20%. Kh\u00f4ng x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c tr\u01b0\u1eddng h\u1ee3p n\u00e0o th\u1ed1i t\u1eeb \u0111\u1ea7u m\u1eaft v\u00e0o trong th\u00e2n. T\u1ea1i v\u00f9ng g\u1ed7 c\u00f3 m\u1eaft, chi\u1ec1u h\u01b0\u1edbng th\u1edb g\u1ed7 b\u1ecb thay \u0111\u1ed5i. \u1edf g\u1ed7 H\u00f4ng do \u0111\u01b0\u1eddng k\u00ednh m\u1eaft th\u01b0\u1eddng nh\u1ecf n\u00ean \u00edt \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn chi\u1ec1u h\u01b0\u1edbng th\u1edb g\u1ed7 v\u00e0 v\u00ec v\u1eady \u00edt \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn ph\u1ea9m ch\u1ea5t g\u1ed7.<\/p>\n

2.4. Quan h\u1ec7 gi\u1eefa bi\u1ec3u hi\u1ec7n tr\u00ean v\u1ecf v\u00e0 c\u00e1c khuy\u1ebft t\u1eadt c\u1ee7a g\u1ed7.<\/em><\/strong><\/p>\n

Nh\u1eefng khuy\u1ebft t\u1eadt c\u1ee7a g\u1ed7 \u0111\u01b0\u1ee3c th\u1ec3 hi\u1ec7n b\u1eb1ng nh\u1eefng v\u1ebft s\u1eb9o tr\u00ean v\u1ecf qua h\u00ecnh d\u1ea1ng, lo\u1ea1i v\u00e0 \u0111\u1ed9 l\u1edbn c\u1ee7a s\u1eb9o ngo\u00e0i v\u1ecf. Trong m\u1ed9t gi\u1edbi h\u1ea1n nh\u1ea5t \u0111\u1ecbnh, ng\u01b0\u1eddi ta c\u00f3 th\u1ec3 s\u01a1 b\u1ed9 bi\u1ebft \u0111\u01b0\u1ee3c t\u00ednh ch\u1ea5t c\u1ee7a nh\u1eefng khuy\u1ebft \u0111i\u1ec3m trong g\u1ed7.<\/p>\n

Hoa h\u1ed3ng trong m\u1ecdi tr\u01b0\u1eddng h\u1ee3p l\u00e0 bi\u1ec3u hi\u1ec7n tr\u00ean v\u1ecf c\u1ee7a m\u1eaft g\u1ed7. Kh\u1ea3o s\u00e1t bi\u1ec3u hi\u1ec7n hoa h\u1ed3ng tr\u00ean v\u1ecf cho th\u1ea5y 91% c\u00e1c tr\u01b0\u1eddng h\u1ee3p c\u00f3 m\u1eaft \u1edf trong g\u1ed7 c\u00f2n 9% kh\u00f4ng th\u1ea5y khuy\u1ebft t\u1eadt; c\u00f3 th\u1ec3 9% \u0111\u00f3 n\u1eb1m khu\u1ea5t trong v\u00e1n s\u1ebb n\u00ean kh\u00f4ng x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c. T\u1ef7 s\u1ed1 \u0111\u01b0\u1eddng k\u00ednh hoa h\u1ed3ng v\u00e0 \u0111\u01b0\u1eddng k\u00ednh m\u1eaft l\u00e0 100\/62, ngh\u0129a l\u00e0 ng\u01b0\u1eddi ta c\u00f3 th\u1ec3 \u0111\u00e1nh gi\u00e1 \u0111\u01b0\u1eddng k\u00ednh m\u1eaft b\u1eb1ng 60-65% \u0111\u01b0\u1eddng k\u00ednh hoa h\u1ed3ng. H\u1ec7 s\u1ed1 t\u01b0\u01a1ng quan gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh c\u1ee7a hoa h\u1ed3ng v\u1edbi chi\u1ec1u d\u00e0i c\u1ee7a m\u1eaft r=”0,73″ v\u00e0 ph\u01b0\u01a1ng tr\u00ecnh t\u01b0\u01a1ng quan tuy\u1ebfn t\u00ednh \u0111\u01b0\u1eddng th\u1eb3ng y= 0,35x + 1,54; trong \u0111\u00f3 y l\u00e0 chi\u1ec1u d\u00e0i m\u1eaft v\u00e0 x l\u00e0 \u0111\u01b0\u1eddng k\u00ednh hoa h\u1ed3ng. Nh\u01b0 v\u1eady, b\u1eb1ng vi\u1ec7c \u0111o \u0111\u1ebfm k\u00edch th\u01b0\u1edbc hoa h\u1ed3ng bi\u1ec3u hi\u1ec7n b\u00ean ngo\u00e0i c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c k\u00edch th\u01b0\u1edbc c\u1ee7a m\u1eaft b\u00ean trong g\u1ed7.<\/p>\n

B\u01b0\u1edbu tr\u00ean c\u00e2y g\u1ed7 H\u00f4ng \u00edt v\u00e0 c\u00f3 k\u00edch th\u01b0\u1edbc nh\u1ecf. Bi\u1ec3u hi\u1ec7n tr\u00ean g\u1ed7 l\u00e0 u g\u1ed7 xo\u1eafn. Nh\u00ecn chung kh\u00f4ng \u1ea3nh h\u01b0\u1edfng nhi\u1ec1u \u0111\u1ebfn ch\u1ea5t l\u01b0\u1ee3ng g\u1ed7. Nh\u1eefng ch\u1ed7 v\u1ecf ch\u1ed3i l\u00ean ch\u00fat \u00edt nh\u01b0ng kh\u00f4ng x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c l\u00e0 b\u01b0\u1edbu r\u00f5 r\u1ec7t trong c\u00e1c tr\u01b0\u1eddng h\u1ee3p \u0111\u1ec1u kh\u00f4ng \u0111\u00e1ng k\u1ec3.<\/p>\n

T\u1ea1i nh\u1eefng ch\u1ed7 v\u1ecf c\u00f3 ch\u00fat \u00edt bi\u1ebfn d\u1ea1ng m\u00e0 kh\u00f4ng c\u00f3 bi\u1ec3u hi\u1ec7n \u0111\u1eb7c bi\u1ec7t th\u00ec c\u00f3 t\u1edbi 85% l\u00e0 g\u1ed7 kh\u00f4ng c\u00f3 khuy\u1ebft t\u1eadt c\u00f2n 15% c\u00e1c tr\u01b0\u1eddng h\u1ee3p l\u00e0 che \u0111\u1eady m\u1ed9t khuy\u1ebft \u0111i\u1ec3m n\u00e0o \u0111\u00f3 trong g\u1ed7 nh\u01b0 m\u1eaft nh\u1ecf, khuy\u1ebft t\u1eadt do s\u00e2u b\u1ec7nh hay do t\u00e1c \u0111\u1ed9ng c\u01a1 gi\u1edbi.<\/p>\n

III. K\u1ebft lu\u1eadn<\/p>\n

– G\u1ed7 H\u00f4ng c\u00f3 \u00edt khuy\u1ebft t\u1eadt t\u1ef1 nhi\u00ean v\u00e0 c\u00e1c khuy\u1ebft t\u1eadt t\u1ef1 nhi\u00ean th\u01b0\u1eddng nh\u1ecf n\u00ean kh\u00f4ng \u1ea3nh h\u01b0\u1edfng nhi\u1ec1u \u0111\u1ebfn ph\u1ea9m ch\u1ea5t g\u1ed7, ph\u1ea7n g\u1ed7 l\u00e0nh m\u1ea1nh nhi\u1ec1u, kh\u1ea3 n\u0103ng l\u1ee3i d\u1ee5ng g\u1ed7 cao.<\/p>\n

– G\u1ed7 H\u00f4ng ph\u00e2n c\u00e0nh s\u1edbm, nh\u1ea5t l\u00e0 n\u01a1i \u0111\u1ea5t tr\u1ed1ng v\u00ec v\u1eady c\u1ea7n che b\u00f3ng trong n\u0103m \u0111\u1ea7u v\u00e0 ch\u1ee7 \u0111\u1ed9ng t\u1ec9a c\u00e0nh nh\u1eb1m t\u0103ng ph\u1ea7n th\u00e2n g\u1ed7 l\u00e0nh m\u1ea1nh, m\u1eaft g\u1ed7 nh\u1ecf v\u00e0 kh\u00f4ng b\u1ecb th\u1ed1i.<\/p>\n

– C\u1ea7n c\u00f3 nghi\u00ean c\u1ee9u th\u00eam v\u1ec1 khuy\u1ebft t\u1eadt t\u1ef1 nhi\u00ean c\u1ee7a g\u1ed7 H\u00f4ng \u1edf c\u00e1c n\u01a1i kh\u00e1c. Nghi\u00ean c\u1ee9u khuy\u1ebft t\u1eadt gia c\u00f4ng ch\u1ebf bi\u1ebfn, th\u1eddi \u0111i\u1ec3m khai th\u00e1c h\u1ee3p l\u00fd \u2026 l\u00e0 \u0111i\u1ec1u c\u1ea7n thi\u1ebft \u0111\u1ec3 c\u00f3 k\u1ebft lu\u1eadn t\u1ed5ng h\u1ee3p v\u1ec1 g\u1ed7 H\u00f4ng.<\/p>\n

Summary:<\/em>Paulownia fortunei<\/em>is currently much planted in Vietnamas well as in some other countries in the region as it has wide ecological range and is at the same time a fast growing species, the wood of which can meet the raw material requirement of many industries.<\/h1>\n

To investigate the possibility of full use of the wood of this species, we have carried out the study on the natural defect of the wood from trees harvested in Ngan Son District, Cao Bang province. With the results obtained, we note that P. fortunei<\/em> is a large timber species, fast growing with few natural wood defects. The wood defects are usually slight and thus little affect wood quality. Ratio of healthy wood is high allowing high ratio of wood used. Other characteristics of P. fortunei<\/em> wood need be studied to have a comprehensive conclusion on it.<\/p>\n

T\u00e0i li\u1ec7u tham kh\u1ea3o<\/h3>\n

1. K. Esau, 1965. Plant anatomy, 2nded<\/sup>, Wiley.<\/p>\n

2. Lutz- Harman, 1962. Nh\u1eefng \u0111i\u1ec1u c\u1ea7n l\u01b0u \u00fd khi s\u1eed d\u1ee5ng g\u1ed7 l\u00e1 to. NXB N\u00f4ng th\u00f4n.<\/p>\n

3. V\u0169 H\u00e2n, 1964. Ki\u1ebfn th\u1ee9c c\u01a1 b\u1ea3n v\u1ec1 g\u1ed7. NXB Khoa h\u1ecdc<\/p>\n

4. TCVN 1074 \u2013 86. G\u1ed7 tr\u00f2n – Ph\u00e2n c\u1ea5p ch\u1ea5t l\u01b0\u1ee3ng theo khuy\u1ebft t\u1eadt<\/p>\n

**************************************************<\/p>\n","protected":false},"excerpt":{"rendered":"

Cây Hông ( Paulownia fortunei Hemsl) thu\u1ed9c h\u1ecd Hoa mõm chó (Scrophulariaceae), là cây g\u1ed7 l\u1edbn, cao 20-30m, \u0111\u01b0\u1eddng kính 50-60cm th\u1eadm chí có cây \u0111\u01b0\u1eddng kính trên 100 cm. Cây \u1edf tu\u1ed5i 10 có th\u1ec3 \u0111\u1ea1t th\u1ec3 tích 0,4-0,5 m3. Phân b\u1ed1 ch\u1ee7 y\u1ebfu \u1edf Trung Qu\u1ed1c, Vi\u1ec7t Namvà Lào. \u1edf Vi\u1ec7t Nam, cây Hông có m\u1eb7t \u1edf các vùng B\u1eafc Trung b\u1ed9, Tây B\u1eafc, Trung tâm, \u0110ông B\u1eafc b\u1ed9, n\u01a1i có \u0111\u1ed9 cao 300-1300m, l\u01b0\u1ee3ng m\u01b0a 1500-1850mm, nhi\u1ec7t \u0111\u1ed9 trung bình n\u0103m 20-230C. <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/8591"}],"collection":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/comments?post=8591"}],"version-history":[{"count":2,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/8591\/revisions"}],"predecessor-version":[{"id":19310,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/8591\/revisions\/19310"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/media?parent=8591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/categories?post=8591"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/tags?post=8591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}