KHOA HOC C O N G NGHE
XAC D!I\IH PHAM TRAM SO CAY/SO CAY CAiXI DO CHIEU CAO VIJT IXIGOIM DE LAP PHUOIMG TRIIVH
TU01MG QUAIM H - D
Cao Tin Thu Hiln^ Ph?im Th^ AnhS Vu Tife Himg^
TOMTAT
Bai bao gidi thieu ket qua nghien cmi vd tim phuong trinh tdt nhat de md ta moi quan he gitia chidu cao viit ngon va dudng kinh ngang nguc ciia bon trang thai rimg la rimg ngheo, rimg trung binh, rimg giau va rimg rat giau. Xac dmh phan tram so cay trong m6i 6 do d^m va sd cay cr m6i ca duong kinh can do chi^u cao de xac lap mdi quan he nay. Ket qua cho thay (1) phuong hinh (2.4) // = a, [In (D)]*" duac chon de mo ta mdi quan h§ giiia chieu cao viit ngpn va dudng Idnh ngang nguc cho 4 trang thai rung trong nghien cuu nay. (2) Trong qua trinh dieu tra, cd the chi can do dem chi^u cao viit ngon ciia 30% sd cay cd trong OTC de xac lap mdi quan he giua chi6u cao vut ngon va dudng kinh ngang nguc. (3) Neu xac dinli theo sd cay d mdi ca dudng kinh, cd the chi can do dem chi6u cao viit ngpn ciia 10,11 hoac 12 cay o mdi cap dudng kinh c6 trong OTC de xay dung phuang trinh mo ta mdi quan he giua chi6u cao vut ngpn va dudng kinh ngang nguc.
Tii khda: Mdi lien he H- D, phan tram sdcay cdn do chieu cao, sdcay can do chieu cao, rung ngheo, rirng giau.
l.gATVANDE
Chieu cao cay rimg la mpt dai lirpng sinh truong hieu thi ket qua smh truong vi chi^u cao tai mot thcri diem xac dmh cua cay rimg. Cung nhu duong kinh, tiet dien ngang, the tich than cay,... chieu cao cay la mot nhan td dieu tra bien doi theo thai gian. Sinh tnrong chi6u cao cay trong lam phan phu thuoc vao loai cay, dieu kien lap dia, tuoi va mat do. Su khac biet vi chiin cao trong lam phSn ngoai phu thuoc vao duong kinh con phu thuoc vao vi tri sinh truong va cac yeu to khac. Chi6u cao cay rimg la can cu quan trong d^ tinh toan cac loai chigu cao binh quan lam phan.
Mu6n xac dmh trii luong chung ciing nhu trii luong lam phan, can thu thap so heu vi chieu cao cua cac cay trong lam phdn. Khac voi duong kinh, ch\hi cao viit ngon than cay dung thuong chi xac dmh gian hep bang cac dung cu do va ton kem thoi gian. Do do, de don gian cho cong tac di^u tra thi can phai tim hieu moi quan ht giira chi6u cao viit ngpn than cay diing voi mot so nhan td diin tra khac di do dim hon nhu la duong kinh ngang nguc. Do vay, viec nghien cuu cac quy luat tuong quan giiia cac dai lirpng cdn do ddm cua cac cay trong lam phan nhSm
Bd mdn Di6u tra - Quy hoach rimg. Khoa Lam hpc, Trudng Dai hpc Lam nghiep
mue dich xay dung phuong phap xac dinh cac dai luong kho do dem nhir chi^u cao viit ngon than cay dung tir nhirng dai luong de do hoac tinh toan don gian.
Giiia chi^u cao viit ngpn va duong Idnh ngang nguc cua cay rimg tdn tai mdi lien he chat che. Mdi hen he nay khong chi gidi han trong mpt lam phan ma tdn tai trong tap hpp nhi^u lam phan va khi nghien cuu khong can xet ddn hoan canh va tudi.
Thuc ti6n cho thdy, c6 the dua vao mdi quan he giira chieu cao viit ngpn va dudng kinh ngang nguc d^ xac dinh chieu cao tuong ung cho tung ca dudng kinh, ma khong cdn thiet phai do chidu cao vut ngon cho toan bp.
Vay cau hdi dat ra la (1) dang phuong trinh nao la tdt nhdt de mo ta quan he giiia chidu cao viit ngpn vdi dudng kinh ngang nguc ( H - D ) , (2) phai do chidu cao viit ngpn ciia bao nhieu phdn tram sd cay trong lam phan de xac lap quan he H - D va (3) b mdi CO duong kinh tlii cdn phai do chieu cao viit ngon cua bao nhieu cay de co the xac lap quan he H - D? De giai quyet dupe ba cau hdi dat ra, mue tieu cua nghien cuu nay se di tim phuong trinh toan hoc cu the bieu thi quan he giira chidu cao viit ngon - duong kinh ngang nguc phu hop nhat va xac dinh duoc phdn tram sd cay cd trong 6 do ddm hoac sd
cay b mdi cb kinh cdn phai do de cd the xac lap diroc mdi lien hd nay.
Z.PHUQNBPHAPNGHBUCUU 2.1. Phuong phdp thu th$p sd Udu
Ddi tupng trong nghifen cuu nay la 4 trang thai rirng la rimg rat giau, rung giau, rimg trung binh va rimg ngheo. Nghien cim su dung sd heu didu tra d 20 6 Ueu chuan (OTC), dien tich moi OTC la 1 ha. Mdi trang thai lap 5 OTC, mdi OTC co hinh vu6ng (100 m X 100 m) va dup€ phan chia thanh 25 phan 6 20 m x
20 m. Trong mdi OTC hen hanh xac dinh ten loai cho tat ca cac cay cd dudng kinh 6 cm trd len, do dudng kinh ciia tat ca cac cay cd duong kinh tir 6 cm trd len bang thuoc kep kinh do chinh xac 0,5 cm, do chidu cao cua tat ca cac cay cd dudng kinh tir 6 cm trd len bdng thudc do cao Blumeleiss voi do chinh xac 0,5 m.
Sd heu dimg trong nghien cuu nay duoc thdng ke trong bang 1.
I Tinh Tuy6n Quang Tuyen Quang Ha Tmh Hoa Binh Hda Binh Quang Binh Quang Binh Quang Bmh Ha Tmh Ha Tmh
Jang 1. PI OTC
1 2 3 4 5 1 2 3 4 5
lan bd sd OTC theo dia phirong vd theo trans thdi rung Trang thai rimg
Ngheo Ngheo Ngheo Ngheo Ngheo Trung binh Trung binh Trung hinh Trung binh Trung binh
Tinh Quang Bmh Quang Binh Thira Thien - Hue Thira Thien - Hue Thiia Thien - Hue Gia Lai Gia Lai Gia Lai Gia Lai Gia Lai
OTC 1 2 3 4 5 1 2 3 4 5
Trang thai rimg Giau Giau Giau Giau Giau Rat giau Rat giau Rat giau Rat giau Rdt giau 2.2. Phuong phap xii ly sd Ii§u
2.2.1. Lap phuong trinh tuong quan 0ira chieu eao vut ngon vdi dudng kinh ngang nguc
Phuong trinh toan hoc cu thd bieu thi quan he nay rdt phong phii va da dang. De tim dupe phuong trinh bieu di^n mdi quan he giCra chieu eao viit ngpn va duong kinh ngang nguc tdt nhat, trong nghien cuu nay se thu nghiem 6 dang phuong trinh sau:
Cac dang ham sau duge dimg de thii nghiem:
// = a + b. In (D) (2.1) H^a.D^ (2.2) H ^a + b. IniD) + c. [In (D)]2(2.3) H = a.[ln(D)]'' (2.4) / / - a . e - " ^ ^ ' ^ (2.5) // = 1.3-l-o.e-*^'° (2.6) 2.2.2. Phuong phap ehon phuong tiinh tdt nhat Phuong trinh dupe chpn dd bieu didn mdi quan he giiia chidu cao viit ngpn va dudng kinh ngang nguc can thoa man 2 didu kien sau;
- Dieu kien 1: Dua vao he sd xac dinh R^; Vi bidn phu thuoc trong nghien cuu nay deu gidng nhau la
ehieu cao viit ngpn (H) n^n cd the dua vao he sd xac dinh de chon phuong trinh phii hpp nhat. Phuong trinh dupe chon la phuong trinh co he sd xac dinh R^
Ion nhat.
- Didu kifen 2: Dua vao tdng sai lech bmh phuong giira gia tri ly thuyet voi gia tri quan sat dupe tinh theo cong thiic:
RSS =^'ZiH,-Hi_ry (2.7) Trong cong thuc (2.7), H, la gia tri chieu cao do thuc te, H,i- la gia tri chieu cao ly thuyet dupe udc luong theo 6 phuong trinh thir nghiem.
Phuong trinh cang thich hpp thi gia tri chidu cao ly thuyet cang gan voi gia tri chidu cao do thue te.
2.2.3. Xac dinh ty le phin tram sd cay can dieu tia chieu cao viit ngon tiong lam phan de xic lap quan bd H-D
- Khi da tim duoc phuong trinh tot nhat de mo ta quan he H - D d npi dung thir nhat, dimg phuong trinh dd de uoc lupng gia tn chieu cao ly thuyet cho tat ca cac cay Q-ong mdi OTC. Sau do, lay 20%, 30% va 40% sd eay cd trong mdi OTC theo phuong phap he thdng. Tinh gia til trii luong ly thuyet ciia 20%, 30% va 40% sd cay dupe chpn. Xac dmh sai so tuong ddi giua gia tri trir lupng thuc va cac gia tri ti-u lupng ly thuyet cua cac cay duoc lay mdu theo cong thuc (2.8).
118 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2018
KHOA HOC CONG NGHE
a%=^te^.ioo
(2.8) Trong cong tiiuc (2.8), Mn la gia hi hrir luong thuc te, MLT la gia tri trir lupng ly thuyet duoc udc lugng theo phuong da dupe chpn d mue (2.2.2).Gia tri trir lupng thuc te duoc tinh thong qua the tich cua tiing cay trong mdi OTC theo cong thirc cua GS.TS. Vu Tidn Hmh (2012) nhu sau:
V = 0,00006341 X D^'«™ x H"'^^''^ (2.9) M-rr = IV, (2.10) - Tiep theo, chia cac cay trong mdi OTC theo 5
cap kinh, sau do chpn 10,11 hoac 12 cay cho m6i cap
kinh theo phuong phap ngdu nhi6n don gian. Diing gia tri chieu eao ly thuyet ciia 10, 11 hoac 12 cay dupe chpn b mdi cap kinh de udc luong trir lupng ly thuyet va xac dinh sai sd tuong ddi giiia gia tn trir lupng thuc va cac gia tri trii lupng ly thuyet cua cac cay dupe lay mdu theo cdng thuc (2.8)
3. KFT QUA VA THAO LUAN
3.1. Lap phuong trinh hrong quan giiia chidu cao viit ngpn vdi dudng kinh ngang nguc
Kdt qua thir nghiem 6 dang phuong trinh tuong quan giira chidu cao vut ngon va dudng kinh ngang nguc dupe tdng hop trong bang 2.
Bangs Trang thai
rimg
Rimg ngheo
.K^tquatl OTC
1
2
3
4
5
lit nghifem moi Mn h^ HVN - D Dang phirong
trinh 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2,6
TC 0,665 0,657 0,665 0,665 0,667 0,660 0,873 0,846 0,874 0,877 0,875 0,875 0,782 0,785 0,788 0,788 0,788 0,750 0,640 0,681 0,653 0,674 0,650 0,619 0,633 0,679 0,635 0,678 0,635 0,621
1 cho 4 trang thii rimg th Tham so cua phuonj
a -5,18 2,58 -2,62 2,59 35,57 18,88 -7,00 2,38 -11,39
2,36 25,22 20,79 -10,41 4,09 2,66 3,07 216,89
32,03 -1,37 4,16 13,76 4,79 3042,42
19,91 -0,88 4,28 1,25 4,86 504,76
19,72 b 6,11 0,54 4,14 1,48 4,22 9,92 6,93 0,58 10,29 1,60 6,42 10,02 9,38 0,48 0,86 1,58 4,66 12,94 5,89 0,45 -6,59 1,09 6,70 5,85 5,70 0,44 0,88 1,08 4,89 5,70
eo 6 dang p
; trinh c
0,37 0,48
-0,63 0,79
1,34 0,20
2,50 0,08
0,12
hirong trinh RSS 2,93 3,00 2,94 2,93 2,93 2,97 1,00 1,21 1,99 1,05 1,99 1,99 8,90 8,76 8,82 8,67 8,82 10,16 7,12 7,03 6,95 6,03 7,00 7,39 9,03 8,61 7,42 7,11 7,18 7,34 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2018
Rimg trung binh
Rimg giau 1
2
3
4
5
1
2
3
2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5
0,687 1 -5,59 0,707 ' 2,90 0,708
0,707 0,706 0,655 0,847 0,855 0,856 0,856 0,856 0,808 0,793 0,796 0,798 0,798 0,798 0,771 0,751 0,719 0,825 0,883 0,855 0,768 0,725 0,765 0,725 0,774 0,728 0,726 0,921 0,896 0,921 0,922 0,923 0,913 0,706 0,694 0,707 0,707 0,709 0,698 0,718 0,707 0,720 0,720
9,61 2,82 5553,40
21,80 -2,80 3,76 4,40 3,74 1141,30
20,25 -11,83 3,58 1,37 2,65 253,41
32,38 -6,67 3,43 16,13 4,25 64,29 27,41 -11,83 2,15 -11,47 2,10 40,10 29,33 -9,31 2,48 -7,00 2,16 42,53 24,73 -6,79 3,17 -3,76 2,94 44,31 24,14 -5,37 3,69 -1,68 3,44 0.722 1 51,36
6,74 0,53 -4,76 1,49 7,77 9,36 5,85 0,45 0,30 1,24 5,92 7,57 9,60 0,51 1,06 1,67 4,96 14,10 7,65 0,50 -8,89 1,19 4,50 11,61 9,54 0,67 9,27 1,87 6,59 12,40
7,95 0,57 6,27 1,72 5,32 11,90 7,46 0,52 5,19 1,51 4,38 9,88 7,14 0,48 4,36 1,39 3,89
2,09 0,09
1,02 0,10
1,33 0,20
2,90 0,39
0,06 0,68
0,29 0,53
0,41 0,48
0,50 0,40
5,80 5,48 5.47 5,46 5,50 6,45 2,49 2,35 2,39 2,32 2,39 3,12 9,95 9,78 9,88 9,69 9,89 10,98
6,05 5,02 6,63 3,02 3,21 3,63 8,57 8,01 8,03 8,00 8,48 8,51 1,50 1,97 1,50 1,44 1,46 1,66 7,21 7,52 7,20 7,13 7,15 7,42 5,85 6,09 5,83 5,71 5,78 120 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2018
KHOA HOC CONG NGHE
Rimg rat giau
4
5
1
2
3
4
5
2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 2.5 2.6
0,701 0,709 0,694 0,709 0,709 0,710 0,695 0,712 0,718 0,720 0,720 0,720 0,688 0,702 0,704 0,708 0,708 0,687 0,682 0,744 0,736 0,745 0,745 0,725 0,720 0,622 0,633 0,633 0,626 0,594 0,585 0,662 0,658 0,665 0,665 0,648 0,648 0,716 0,715 0,719 0,719 0,697 0,694
23,70 -4,25 4,06 -3,59 3,82 41,01 23,14 -6,43 3,06 3,26 2,76 233,35
22,95 -13,74 3,34 3,21 2,44 21,87 33,29 -11,58 4,90 -5,20 3,54 25,60 35,73 -5,22 5,09 13,49 4,12 21,98 27,59 -13,91 3,37 -1,99 2,46 21,27 33,38 -13,03 4,03 0,75 3,00 23,41 35,00
8,93 6,76 0,45 6,27 1,30 3,74 8,36 7,04 0,51 0,01 1,51 4,84 10,21 10,30 0,53 -0,60 1,76 0,81 14,42 10,30 0,45 6,32 1,53 0,98 13,15
7,52 0,40 -4,46 1,30 0,99 10,25 10,39 0,53 2,71 1,76 0,70 14,37 10,61 0,50 1,75 1,65 0,85 13,36
0,09 0,46
1,23 0,18
1,70 0,46
0,60 0,51
1,86 0,56
1,20 0,43
1,38 0,49
6,21 6,01 6,32 6,02 6,01 5,99 6,29 5,53 5,42 5,38 5,09 5,38 5,99 12,28 12,17 12,06 12,05 19,89 13,10 12,13 12,51 12,10 12,09 35,23 13,25 10,40 10,10 10,12 10,10 20,70 11,40 13,53 13,69 13,45 13,42 33,64 14,10 12,10 12,12 12,96 12,05 33,63 13,00
Bang 2 cho tiidy, phan Idn ta hai phuong trinh la (2.3) va (2.4) cd he sd xac dinh cao nhdt. Trong do, he sd xac dinh cua phuong tiinh (2.4) bdng hoac Idn hon mpt chiit so vdi he sd xac dinh cua phuang trinh (2.3).
Dua vao gia tri Zifi^ - H^jY cung cho thay, phuong trinh (2.4) cd tdng binh phuong giua gia tri ly thuydt vdi gia tii quan sat la nhd nhdt.
Nhu vay, phuong tiinh (2.4) dupe chpn dd mo ta mdi quan he giiia chieu cao viit ngon va dudng kinh ngang nguc cho 4 trang tiiai rimg trong nghien cuu nay.
Cac dang phuong trinh dupe lira chpn de thu nghiem ti'ong nghien cuu nay cung da duoc cac tac gia khac b tren tiie gidi nhu: Naslund, M., (1929), Assmanm, E., (1936), Hohenadl, W., (1936), Prodan, M., (1944), Meyer. H. A., (1952) da dd nghi tiiu nghiem cac dang phuong trinh nhu phuong trinh (2.1), (2.2) trong nghien ciru nay, hay vdd dang ham (2.1) cung cd cac tac gia Curtis (1967), Fang va Bailey (1998) da dimg de xac lap quan he H - D. Vdi
su (2001), Fang va Bailey (1998) thir nghiem. Dang ham cua Chapman - Richards (phuong trinh 2.5) dupe cac tac gia Batista va cpng su (2001), Huang va Titiis (1992) thu nghiem. (d Vi6t Nam Nguyin Thanh Men (2005) khi nghien cuu cau tnic rimg tiJ nhien la rpng thudng xanh sau khai thac d tinh Phu Yen cQng da sic dung hai trong cac dang phuong trinh tuong tir trong nghien ciiu nay la (2.1) va (2.2). Tuy nhien, cac dang phuong trinh (2.3), (2.4), (2.5) va phuong tiinh Michailov (2.6) thi chua dupe tac gia nao d Viet Nam thu nghiem de xac lap mdi quan he H - D.
3.2. K^t quS xac dinh sai sd tuong d^i giua gid tri trii lupng thuc vk ckc gid tri trii lupng I;^ thuydt
3.2.1. Ket qua xic dinh sai sd tucmg ddi giua gi^
tii tru luong thue va cic gii tii tru luong ly thuyet theo 20%, 30% vi 40% sdcay trong mdi OTC
Ket qua xac dinh sai sd tuong ddi gitia gia tri trii lupng thuc va cac gia tri trii luong ly thuyet cua 20%, 30% va 40% sd cay dupe lay mau theo cong thue (2.8) dupe tdng hpp trong bang 3.
dang ham (2.2) da duoe cac tac gia Batista va cong
Bang 3. Kdt qua xac dinh sai sd tuong ddi gifia gid trj hii lupng thuc va cdc gid hi tiii lupng ly thuydt theo 2096, 30%va40%sdcay
Trang thai rimg Rimg ngheo Rimg ngheo Rimg ngheo Rimg ngheo Rimg ngheo Rimg trung binh Rimg trung binh Rimg trung binh Rimg trtmg binh Rimg trung binh Rimg giau Rimg giau Rimg giau Rimg giau Rimg giau Rimg rat giau Rimg rat giau Rimg rat giau Rimg rat giau Rimg rat giau
OTC 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
Trir lugng thirc 69,95 50,52 73,57 91,04 94,64 129,65 146,95 108,35 121,96 101,43 225,68 209,73 210,82 224,23 213,30 345,52 644,49 351,83 355,37 483,23
Sai s6 theo 20% sd cay 3,57 2,88 1,03 2,51 1,30 8,40 0,64 1,85 1,69 3,09 4,41 5,72 1,56 0,92 7,01 1,93 3,46 0,35 3,40 1,54
Sai so theo 30% sd cay
0,77 0,07 3,52 4,61 1,04 3,37 2,90 0,28 4,00 0,39 0,83 3,92 1,17 0,44 0,27 1,13 2,82 0,74 0,08 1,30
Sai sd theo 40% sd cay
1,11 2,06 4,85 0,25 2,57 1,70 2,14 2,58 1,21 3,28 5,76 5,72 3,15 5,50 1,70 6,29 1,91 2,13 1,07 3,61 Bang 3 cho thay, sai sd tuong ddi giiia gia tri trir
lirong thuc va cac gia tri trir luong ly thuyet cua 20%,
30% va 40% sd cay trong mdi OTC phan Ion la khdng vuHt qua 5%, ngoai trir 3 OTC la OTC 1 cua trang thai 122 NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 - THANG 11/2018
KHOA HOC CdNG NGHl rimg hnng binh, OTC 2 va OTC 5 cua trang thai
rimg ngheo (ddi voi trudng hop Idy mdu la 20% sd cay) va 4 OTC la OTC 1, OTC 2, OTC 4 cua ti-ang thai rimg giau va OTC 1 cua trang thai rimg rat giau (ddi vdi hirdng hpp \iy mdu la 40% sd cay) la cd sai sd tuong ddi Idn hon 5%. Trudng hpp lay mdu la 30%
sd cay trong mdi OTC, khong cd OTC nao co sai sd tuong ddi Idn hon 5%. Nhu vay, trong qua trinh dieu tra, can do ddm tdi thidu chieu cao cua 30% sd cay cd
trong OTC de xac lap mdi quan hd giira chidu cao vut ngon va dudng kinh ngang nguc.
3.2.2. Ket qua xic dinh sal sd tuong ddi giua gii tri tru luong thuc va cic gii tii tru lupng ly thuyet theo 10,11 vi 12 sd cay cho ttmg cap kinh tiong mdi OTC
Ket qua xac dinh sai sd tuong ddi giira gia tri trii lupng thuc va cac gia tn trii lupng ly thuyet cua 10, 11 va 12 cay dupe Idy mdu d mdi cap kinh theo cong thirc (2.8) dupe tdng hpp trong bang 4.
Bang 4. K^t qua xdc dinh sai sd tucmg ddi gitia gid tri trii lupng thuc vd cdc gid tri trii lupng ly thuydt cua 10, 11 vd 12 cdy dupe l^y mdu dmdi cap kinh
Trang thai rimg Rimg ngheo Riing ngheo Rimg ngheo Rimg ngheo Rimg ngheo Rimg trung binh Rimg trung binh Rimg trung binh Rimg trung binh Rimg trung binh Rimg giau Rimg giau Rimg giau Rimg giau Rimg giau Rimg rat giau Rimg rat giau Rimg rat giau Rimg rat giau Rimg rat giau
OTC 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
Tru luong thuc 69,95 50,52 73,57 91,04 94,64 129,65 146,95 108,35 121,96 101,43 225,68 209,73 210,82 224,23 213,30 345,52 644,49 351,83 355,37 483,23
Sal sd theo miu 10 cay
0,67 1,37 1,70 0,28 0,56 2,45 1,04 1,05 0,70 1,70 1,14 2,45 0,03 0,46 0,47 0,23 0,20 0,66 0,65 0,45
Sai sd theo mlu 11 cay
2,22 0,08 0,64 3,52 3,73 0,91 1,19 1,12 1,64 0,64 1,33 0,91 5,00 0,30 1,62 1,27 1,04 2,07 0,35 0,68
Sai sd theo mau 12 cay
1,50 0,06 3,12 2,60 0,14 0,74 1,14 1,02 0,72 3,12 1,29 0,74 2,88 0,11 0,20 0,15 0,68 1,21 1,77 2,09 Bang 4 cho thay, sai sd tuong ddi gitia gia tri tru
iupng thuc va cac gia tri trii lupng ly thuydt cua ca 3 trudng hpp la lay 10,11 hoac 12 cay d mdi cap dudng kinh deu khong vuot qua 5%. Nhu vay, trong qua trinh didu tra, can do dem tdi thidu chieu cao cua 10, 11 hoac 12 cay d mdi cap dudng kinh cd trong OTC dd xay dung phuong hinh mo ta mdi quan he giiia chieu cao viit ngon va dudng kinh ngang nguc.
4. KETLUAN
Phuong tiinh (2.4) H = a. [in ( D ) ] ^ dupe chpn de md ta mdi quan he giira chidu cao viit ngpn
va dudng kinh ngang nguc cho 4 trang thai rimg trong nghien ciru nay.
Trong qua trinh dieu tra, can phai do dem tdi thieu chidu cao vut ngon cua 30% sd cay cd trong OTC de xac lap mdi quan hd giua chieu cao vut ngon va dudng kinh ngang nguc.
Neu xac dinh theo sd cay d mdi co dudng kinh, can do dem toi thieu chieu cao viit ngon cua 10, 11 hoac 12 eay b mdi cdp dudng kinh cd trong OTC de xay dung phuong trinh mo ta mdi quan he giira chieu cao vut ngon va dudng kinh ngang nguc.
TAI Lni1)MI\l KHAO of trees in natural tropical forest in Tanzania 1. Bd Ndng nghiep va PTNT, 2009. Thdng tu sd Southern Forests: a Journal of Forest Science 75, 221 34/2009/TT-BNNPTNT Quy dinh tieu chi xac dinh " 237.
va phan loai rimg. g Scaranallo, M. A. da S., Alves, L F., Vieu-a, S.
2. Cao Thi Thu Hidn, 2015. Struchiral analysis A.. Camargo, P. B., Joly, C. A., MarUnelli, L. A.
and growth modeling of natural forests in Vietnam (2012). Height - diameter relationships of tropical [Dissertation]. Georg-August-Universitat Atlantic moist forest trees in southeastern Brazil Goettingen, Goettmgen, Germany. Scientia Agricola 6 9 , 2 6 - 3 7 .
3. Curtis, R. 0., 1967. Height-diameter and 7. Vu Tidn Hinh, Pham Ngoc Giao, 1997. Giao height-diameter-age equations for second-growth t™li Bieu tra rimg. Nha xuat ban Ndng nghiep.
Douglas-Fir. Forest Science 13, 365-375. 8. Vu Tien Hinh, 2012. Phuong phap lap bieu the 4. Fang, Z., Bailey, R. L., 1998. Height-diameter ^ch cay diing rimg tir nhien d Vidt Nam. Nha xuat models for tropical forests on Hainan Island m ban Ndng nghiep.
southern China. Forest Ecology and Management 9. Vu Tien Hung, 2015. Xay dung co sd khoa hpc 110, 315-327. cho dieu tra sinh khdi va cac bon cay diing rimg tu 5. Mugasha, W. A , BoUandsas, 0 . M, Fid, T. "hien la rdng thudng xanh o Viet Nam. Luan an Uen (2013). Relationships between diameter and height ^> Lam nghidp, Trudng Dai hoc Lam nghiep, 2015.
DETERMINATION OFTHE PERCENTAGE OF TREES/NUMBER OF TREES NEEDS TO BE MEASURED TOTAL TREE HEIGHTTO CONSTRUCTTHE RELATIONSHIP BETWEEN HEIGHT AND DIAMETER
Cao TTii Thu Hien, Pham The Anh, Vu Tien Hung Summaty
This paper presents the results of the study on finding the best equation for describing ihe relation between total tree height and diameter at breast height of four forest states: poor forests, medium forests, nch forests and extremely rich forests. Besides, the article also defines the percentage of trees in each sample plot and the number of trees m each diameter ciass that needs to be measured the total tree height to construct this relaUonship. The results showed that (1) equaUon (2.4) H = a. [in (D}J is chosen to describe the relaUonship between the height and diameter for the 4 forest states in the study. (2) During the inveshgation, it is possible to measure only die total Uee height of 30% of the trees in the sample plot to build the relationship between height and diameter (3) If based on the number of trees m each diameter class, we only need to measure height of 10, 11 or 12 trees at each diameter class in the sample plot for building the relaUonship between height and diameter
Keywords: Relationship between height and diameter, percentage of trees needs to be measured height number of trees needs to be measured height, poor forests, rich forests.
Ngtiin phan bien: TS. Vii Thanh Nam Ngiy nhan ba: 17/9/2018 Ngay thdng qua phan bidn: 17/10/2018 Ngiy duyet dang: 24/10/2018
124 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2018
