thinning impacts on even-aged stands of eucalyptus in brazil

Thinning Impacts on Even-aged Stands

of Eucalyptus in Brazil

Gilciano S. Nogueira – UFVJM/Brazil Peter L. Marshall – UBC/CanadaValerie Lemay – UBC/CanadaHelio Garcia Leite – UFV/Brazil

João Carlos Chagas Campos – UFV/Brazil

June 21, 2010 Missoula, MT

Western Mensurationists’ Conference

Introduction

Plantation forest in Brazil: 6.6 million hectares, representing 0.8 % of the land area

From 2004 to 2008 the area in eucalyptus plantation increased by 33.1%, or 1.1 million ha

solid wood products is minimal

Introduction

Advances in wood technology and design have allowed various uses of eucalyptus wood as a solid product

Introduction

The demand for wood from large trees has been supported by illegal harvesting in native forests

Consequently, there are also few studies on the impact of thinning in stands of eucalyptus in Brazil

Introduction

Studies of thinning in eucalyptus are strategic for Brazil, both economically and environmentally

Thinning in eucalyptus forests can help increase Brazilian participation in the global market for solid wood products and may reduce pressure on Brazilian native forests

Introduction

An experiment was established to obtain a database reliable for analyzing the difference among thinning treatments and for developing growth and yield models for thinned eucalyptus stands

Requirements: - Selection of the sample units was deliberate (selective sampling), so that

representation of the medium and extreme site conditions is guaranteed

- The sample units were sufficiently large to faithfully represent the silvicultural practices applied to the remainder of the stand

Objective

To analyze the effect of thinning on growth of stand

variables in eucalyptus forests

Overview of the experiment

- Species: Eucalyptus grandis x Eucalyptus urophylla hybrid

- Location: Northeast region of Bahia State, Brazil

Overview of the experiment

- Planting date: June/July 1993

- Date of installation of the permanent plots: September 1995

- Company: Bahia Specialty Cellulose (BSC) (http://www.bahiaspeccell.com)

- Initial spacing between trees: 3.0 X 3.0 m

- Thinnings accomplished: two selective thinnings, in 1998 and 2004

- Final harvest: at the end of 2007

Experimental Design- based on level-of-growing-stock installation standards

- Located in 3 installations, comprising medium and good quality site conditions

Experimental Design

- Replicated randomized complete block with repeated measures- 6 blocks (two in each installation), each one involving two repetitions;

- 4 treatments, corresponding to different basal area percentages removed in each thinning :

Treatment 1: 20% without pruning;

Treatment 2: 35% without pruning;

Treatment 3: 50% without pruning;

Treatment 4: 35% with pruning up to 6.0 meters;

- Each block contained 8 permanent rectangular plots, with an area of 2,600 m2, totaling 48

plots (6 blocks x 2 repetitions x 4 treatments)

- Layout

Experimental Design

Block 1

Block 2

3 2

2 1

1 4

4 3I II

99,28

204,0 m

3 2

1 4

4 3

2 1III IV

99,28

204,0 m

Block 1 Block 2

Block 2Block 1A

3 2

2 1

1 4

4 3III IV

119.0 m

176.8 m

B

C

Experimental Design

- Replicated randomized complete block with repeated measures- 6 blocks (two in each installation), each one involving two repetitions;

- 4 treatments, corresponding to different basal area percentages removed in each thinning :

Treatment 1: 20% without pruning;

Treatment 2: 35% without pruning;

Treatment 3: 50% without pruning;

Treatment 4: 35% with pruning up to 6.0 meters;

- Each block contained 8 permanent rectangular plots, with an area of 2,600 m2, totaling 48

plots (6 blocks x 2 repetitions x 4 treatments)

- Plots were buffered by a few rows of trees on each side

Marked boundaries of a plot

Measurement Year ofmeasurement

Age (month)

Age (year) Note

1 1995 27 2.3 before 1st thinning2 1996 40 3.3 before 1st thinning3 1997 50 4.2 before 1st thinning; 1st stem analysis (6 trees per dbh class)4 1998

61 5.1after 1st thinning

5 1999 75 6.3 after 1st thinning6 2000 87 7.3 after 1st thinning7 2001 100 8.3 after 1st thinning8 2002 111 9.3 after 1st thinning9 2003 124 10.3 after 1st thinning

10 2004 136 11.3 after 1st thinning11 2005 147 12.3 after 2nd thinning12 2006 157 13.1 after 2nd thinning13 2007 164 13.7 after 2nd thinning; 2nd stem analysis (6 trees per dbh class)

- Data

Measurements

After 1st thinning (61 months)

After 1st thinning (87 months)

MeasurementsAfter 1st thinning (101 months)

After 2nd thinning (165 months)

Volume equation

HtLndbhLnVtLn 23523.1751165.1-10.28859 998.02 R

outside bark:

inside bark:

HtLndbhLnVtLn 22368.174249.1-10.39158 998.02 R

Volume equation

Distri b u ti o n o f Ra w re si d u a l s

E xp e cte d No rm a l

-0 .3 0 -0 .2 5 -0 .2 0 -0 .1 5 -0 .1 0 -0 .0 5 0 .0 0 0 .0 5 0 .1 0 0 .1 5 0 .2 00

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

1 8 0

2 0 0

No of obs

P re d i cte d vs. O b se rve d V a l u e sD e p e n d e n t va ria b le : L n V t ib

-5 .0 -4 .5 -4 .0 -3 .5 -3 .0 -2 .5 -2 .0 -1 .5 -1 .0 -0 .5 0 .0

P re d icte d V a lu e s

-5 .0

-4 .5

-4 .0

-3 .5

-3 .0

-2 .5

-2 .0

-1 .5

-1 .0

-0 .5

0 .0

Observed V

alues

9 5 % co n f id e n ce

P re d i cte d vs. Re si d u a l S co re sDe p en d e n t va ri ab l e : L n V tib

-5 .0 -4 .5 -4 .0 -3 .5 -3 .0 -2 .5 -2 .0 -1 .5 -1 .0 -0 .5 0 .0

P re d i cte d V a lu e s

-0 .2 5

-0 .2 0

-0 .1 5

-0 .1 0

-0 .0 5

0 .0 0

0 .0 5

0 .1 0

0 .1 5

0 .2 0

0 .2 5

Residuals

9 5 % co n f i de n ce

Di stri b u ti o n o f Ra w re sid u a l s E xp e cte d No rm a l

-0 .3 0 -0 .2 5 -0 .2 0 -0 .1 5 -0 .1 0 -0 .0 5 0 .0 0 0 .0 5 0 .1 0 0 .1 5 0 .2 0 0 .2 50

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

1 8 0

2 0 0

No of obs

P re d i cte d vs. O b se rve d V a l u e sDe p e n d e n t va ria b l e : L n V to b

-4 .5 -4 .0 -3 .5 -3 .0 -2 .5 -2 .0 -1 .5 -1 .0 -0 .5 0 .0 0 .5

P re d ic te d V a lu e s

-4 .5

-4 .0

-3 .5

-3 .0

-2 .5

-2 .0

-1 .5

-1 .0

-0 .5

0 .0

0 .5

Observed V

alues

9 5 % co n f id e n ce

P re d i c te d vs. Re sid ua l S co re sDe p e n d e n t va ri a b le : L n V to b

-5 -4 -3 -2 -1 0

P re d i cte d V a l ue s

-0 .2 5

-0 .2 0

-0 .1 5

-0 .1 0

-0 .0 5

0 .0 0

0 .0 5

0 .1 0

0 .1 5

0 .2 0

0 .2 5

Residuals

9 5 % co n fid e n ce

outside bark

inside bark

Height equation

dbhdbhLn

SISILnAgeAgeLnHtLn-0.016830.64171

-0.4935512.928360.00231-0.42280-29.32738

97.02 R

Installation A

dbhdbhLn

SISILnAgeAgeLnHtLn0.01233-0.54414

0.6872217.218170.00238-0.45930-38.23811

dbhdbhLn

SISILnAgeAgeLnHtLn0.03013-0.81710

0.4116412.671100.00774-0.85823-32.40495

Installation B

Installation C

97.02 R

98.02 R

Height equation

Distri b u ti o n o f Ra w re si d u a l s E xp e cte d No rm a l

-0 .2 0 -0 .1 6 -0 .1 2 -0 .0 8 -0 .0 4 0 .0 0 0 .0 4 0 .0 8 0 .1 2 0 .1 6 0 .2 00

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

No of obs

P re d i cte d vs. O b se rve d V a lu e s

De p e n d e n t va ri a b l e : L n Ht

2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6

P re d i cte d V a l u e s

2 .0

2 .2

2 .4

2 .6

2 .8

3 .0

3 .2

3 .4

3 .6

Observed V

alues

9 5 % co n f i d e n ce

A

Distri b u ti o n o f Ra w re si d u a l s E xp e cte d No rm a l

-0 .2 0 -0 .1 6 -0 .1 2 -0 .0 8 -0 .0 4 0 .0 0 0 .0 4 0 .0 8 0 .1 2 0 .1 6 0 .2 00

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

No of obs

P re d i cte d vs. O b se rve d V a lu e sDe p e n d e n t va ri a b le : L n Ht

2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6

P re d i cte d V a lu e s

2 .0

2 .2

2 .4

2 .6

2 .8

3 .0

3 .2

3 .4

3 .6

Observed V

alues

9 5 % co n fi d e n ce

P re d ic te d vs. Re si d u a l S co re sDe p e n d e n t va ria b le : L n Ht

2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6

P re d i cte d V a lu e s

-0 .2 0

-0 .1 5

-0 .1 0

-0 .0 5

0 .0 0

0 .0 5

0 .1 0

0 .1 5

0 .2 0

Residuals

9 5 % co n fi d e n ce

B

P re d i cte d vs. Re sid u a l S co re s

2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6

Predic ted Values

-0 .2 0

-0 .1 5

-0 .1 0

-0 .0 5

0 .0 0

0 .0 5

0 .1 0

0 .1 5

0 .2 0

Residuals

9 5 % co n fi d e n c e

Height equation

Distri b u ti o n o f Ra w re si d u a l s

E xp e cte d No rm a l

-0 .2 0 -0 .1 6 -0 .1 2 -0 .0 8 -0 .0 4 0 .0 0 0 .0 4 0 .0 8 0 .1 2 0 .1 6 0 .2 00

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

4 0 0

No of obs

P re d i cte d vs. O b se rve d V a lu e sDe pe n d e n t va ri a b le : L n H t

1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6

P re d i cte d V a lu e s

1 .8

2 .0

2 .2

2 .4

2 .6

2 .8

3 .0

3 .2

3 .4

3 .6

Observed V

alues

9 5 % co n fi d e n ce

P re d i cte d vs. Re sid u a l S co re s

De p e n d e n t va ri a b le : L n Ht

2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6

P re d i c te d V a lu e s

-0 .2 0

-0 .1 5

-0 .1 0

-0 .0 5

0 .0 0

0 .0 5

0 .1 0

0 .1 5

0 .2 0

Residuals

9 5 % co n fid e n ce

C

Growth trendMean per treatment Individual values

Growth trendsMean per treatment Individual values

Growth trendsMean per treatment Individual values

Growth trendsMean per treatment Individual values

Analysis

Variables: - periodic monthly increment (absolute): total height, dominant height,

quadratic mean diameter and volume per tree - periodic monthly increment (percentage): basal area per hectare and

volume per hectare

Periods: A and B1

(61 to 87)3

(147 to 165)2

(87 to 137)1

(61 to 87)2

(61 to 87)

C

Analysis

Anova: Mixed linear model, with thinning as the whole plot factor and period as the split-plot factor

Random effect: block block*thinning Repetition(block*thinning) period period*thinning

Fixed effect: thinning

Pairwise comparisons: Bonferroni test

Effect on periodic increment of average total height

A B C

A: only thinning 35% and thinning 35% + pruning were equal

B and C : Only thinning 20% was different from the other treatments

There is thinning effect

Effect on periodic increment of dominant height

No thinning effect

Effect on periodic increment of quadratic mean diameter

A B C

A, B and C: only thinning 35% and thinning 35% + pruning were equal

There is thinning effect

Effect on periodic increment of basal area per hectare

A B C

A, B and C: only thinning 35% and thinning 35% + pruning were equal

There is thinning effect

Effect on periodic increment of volume per hectare

A B C

A, B and C: only thinning 35% and thinning 35% + pruning were equal

There is thinning effect

Effect on periodic increment of volume per tree

A

A, B and C: only thinning 35% and thinning 35% + pruning were equal

There is thinning effect

B C

Conclusion

No surprise!

Conclusion

Thinning affected the growth of total height, diameter, basal area per hectare, total volume per tree and total volume per hectare, but did not affect the growth of dominant height

Thinning prevented regular tree mortality

Prunning did not affect the growth trend of the variables analyzed

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