3、根據(jù)胸徑與冠幅關(guān)系求適宜營(yíng)養(yǎng)面積、確定保留株數(shù) 一面坡林場(chǎng)利用最小二乘法配置冠徑和胸徑的回歸方程：

999中國(guó)苗木網(wǎng),999miaomu.com

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y = 0.9533+0.118x+0.0013x2

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中國(guó)苗木網(wǎng),999miaomu.com

式中： y—冠徑；

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x—胸徑。

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這是二次拋物線關(guān)系，確定陰向緩坡落葉松人工林按營(yíng)養(yǎng)面積保留的株數(shù)（表5-7）。

中國(guó)苗木網(wǎng),999miaomu.com

該場(chǎng)某小班十四年生落葉松人工林，每公頃有林木株數(shù)為3755株，單株立木最適營(yíng)養(yǎng)面積為3.14㎡，每公頃適宜株數(shù)為3185株，則應(yīng)間伐570株，其間伐強(qiáng)度（按株數(shù)計(jì)算）為15%。

中國(guó)苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

表5-7 落葉松人工林胸徑、冠徑營(yíng)養(yǎng)面積表

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中國(guó)苗木網(wǎng),www.cqhuayin.com

胸徑

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冠 徑

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中國(guó)苗木網(wǎng),www.cqhuayin.com

理論值

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冠 徑

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999苗木網(wǎng),www.cqhuayin.com

實(shí)際值

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離差

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營(yíng)養(yǎng)面積（平方米）

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每公頃株數(shù)，

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按營(yíng)養(yǎng)面積求。

999苗木網(wǎng),999miaomu.com

999苗木網(wǎng),www.cqhuayin.com

7

苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

1.84

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

1.83

苗木網(wǎng),www.cqhuayin.com

+0.1

中國(guó)苗木網(wǎng),999miaomu.com

2.66

苗木網(wǎng),999miaomu.com

3759

999苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

8

999苗木網(wǎng),www.cqhuayin.com

1.97

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

2.02

999苗木網(wǎng),999miaomu.com

-0.5

999苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

3.05

3278

苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

9

苗木網(wǎng),www.cqhuayin.com

2.12

中國(guó)苗木網(wǎng),www.cqhuayin.com

2.10

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),www.cqhuayin.com

0.02

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),www.cqhuayin.com

3.53

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),www.cqhuayin.com

2833

999中國(guó)苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),999miaomu.com

10

苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

2.26

999中國(guó)苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),999miaomu.com

2.24

999中國(guó)苗木網(wǎng),999miaomu.com

0.02

4.01

中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

2494

苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

11

999中國(guó)苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

2.41

999苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),www.cqhuayin.com

2.41

中國(guó)苗木網(wǎng),www.cqhuayin.com

0

999苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

4.56

苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

2193

苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

12

中國(guó)苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),999miaomu.com

2.56

999苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

2.59

999苗木網(wǎng),999miaomu.com

-0.03

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),www.cqhuayin.com

5.13

苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

1949

苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),999miaomu.com

13

999苗木網(wǎng),999miaomu.com

999苗木網(wǎng),www.cqhuayin.com

2.71

苗木網(wǎng),www.cqhuayin.com

2.69

999苗木網(wǎng),999miaomu.com

0.02

苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

5.77

中國(guó)苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

1733

999中國(guó)苗木網(wǎng),999miaomu.com

㈣ 根據(jù)胸高斷面積定量間伐

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測(cè)定林分的樹(shù)高一般比較困難且誤差較大，用角規(guī)辦法測(cè)定林分?jǐn)嗝娣e，可以不設(shè)標(biāo)準(zhǔn)地也不作每木檢尺，便能夠很容易測(cè)得。按經(jīng)營(yíng)目的，分別林分的發(fā)育階段，確定出最適的林分胸高斷面積，再根據(jù)最適的胸

苗木網(wǎng),999miaomu.com

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35

999苗木網(wǎng),www.cqhuayin.com

產(chǎn)

苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),999miaomu.com

產(chǎn)

產(chǎn)

中國(guó)苗木網(wǎng),999miaomu.com

產(chǎn)

產(chǎn)

中國(guó)苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),www.cqhuayin.com

產(chǎn)

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999苗木網(wǎng),www.cqhuayin.com

產(chǎn)

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產(chǎn)

999苗木網(wǎng),www.cqhuayin.com

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999中國(guó)苗木網(wǎng),www.cqhuayin.com

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999苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

于

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中國(guó)苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

·

中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

·

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中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

999苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

999苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

999苗木網(wǎng),www.cqhuayin.com

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),www.cqhuayin.com

中國(guó)苗木網(wǎng),www.cqhuayin.com

苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

999苗木網(wǎng),999miaomu.com

中國(guó)苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),www.cqhuayin.com

30

苗木網(wǎng),www.cqhuayin.com

25

999苗木網(wǎng),999miaomu.com

苗木網(wǎng),www.cqhuayin.com

20

中國(guó)苗木網(wǎng),999miaomu.com

15

中國(guó)苗木網(wǎng),999miaomu.com

999中國(guó)苗木網(wǎng),999miaomu.com

10

999苗木網(wǎng),www.cqhuayin.com

5
0 10 20 30 40 50 60 70 80

中國(guó)苗木網(wǎng),999miaomu.com

苗木網(wǎng),999miaomu.com

林齡年

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注：上虛線表示間伐前，下虛線表示間伐后。

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圖5-1 定期間伐中林分?jǐn)嗝娣e的變化示意圖。

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高斷面積確定間伐強(qiáng)度進(jìn)行間伐。如圖5-1所示，有兩條斷面積水平線，重要的是下面的水平線，因?yàn)樗�限定了每次間伐后的林分?jǐn)嗝娣e。在整個(gè)輪伐期內(nèi)，控制林分密度的計(jì)劃，主要是根據(jù)每次間伐后所保留下來(lái)的斷面積下限所決定。如為了增進(jìn)林木直徑的生長(zhǎng)而又不降低林分總產(chǎn)量，保留斷面積的適宜水平線范圍約在11～40㎡/公頃。一般針葉樹(shù)比闊葉樹(shù)可保留的水平線要高，耐陰樹(shù)種又高于喜光樹(shù)種。例如：云杉、冷杉約在30～40㎡/公頃，而耐陰性差的樹(shù)種到耐陰性強(qiáng)的樹(shù)種為14～30㎡/公頃，喜光闊葉樹(shù)到最耐陰的闊葉樹(shù)為10～23㎡/公頃。

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保留斷面積的多少是否與立地條件有關(guān)，尚無(wú)定論，一般認(rèn)為就同一樹(shù)種而言，立地條件好的林地，保留的斷面積應(yīng)多些。

圖5-2中下限的斷面積水平線，可參考所經(jīng)營(yíng)樹(shù)種的生長(zhǎng)過(guò)程表，或利用該經(jīng)營(yíng)樹(shù)種自然稀疏進(jìn)程規(guī)律，把株數(shù)換算成斷面積，也可以用年齡、胸徑、胸高斷面積等因子的回歸關(guān)系，或根據(jù)實(shí)際調(diào)查材料，用圖解法求得。