Impact of adjacency and green-up constraints

on wood supply in Georgia, USA

Michal Zasada, Chris J. Cieszewski, Roger C. Lowe, Don Reimer

2nd International Conference on Forest Measurements and Quantitative Methods and Management & the 2004 Southern

Mensurationists MeetingHot Springs, AR, June 15-18, 2004

Outline Where are we? What have we already done? Project objectives and assumptions Results we’ve got so far Short discussion

Georgia Located in the southeastern part of the

United States 3rd fastest growing state in the US Total land area: ~150,000 km2 Population: ~8.6 million

Georgia ~ 9.7 million ha in commercial forests

(almost as much as Germany or France) 66% of the total area of the state the highest area of commercial forests in

the US growing stock ~900 million m3 (1/3 of

Germany or France) Avg. volume ~100m3/ha & MAI 3.8 m3/ha annual harvest over 40 million m3 (almost

as this in Germany or France)

Forest ownership structure in Georgia

Public

NIPF

TI

Georgia• Public forests: 7%;

practically no commercial utilization

• Timber industry: 21%; intensive management, planning, harvest scheduling, …

• ~700,000 private owners: 72%; a whole variety of uses, no coordination nor optimization

• Changes: more TIMOs

Current situation rapid changes to the US Southeast harvesting limitations in public forests,

especially in the western part of the country

increasing demand on wood from southern region

fast population growth with associated urban and suburban development - shifts in land uses

Current situation research on possibilities of increasing

forest productivity from shrinking commercial forest areas

investments in silviculture and g&y research more than doubled growth rates of pine plantations and significantly shortened rotation ages

questions related to the forest resource sustainability

Sustainability project “Long-term sustainability analysis of

forest resources in Georgia and assessment of potential effects of riparian zones and other regulatory and business constraints”

Granted in 2001 by the Georgia TIP3 committee

Already in its final stage

Sustainability project Proof of concept Impact of:

SMZs and RBBs Intensive management

The final stage: increased resolution, combined multi-source data, spatial analyses

Sustainability project Data: Landsat TM5, Georgia GAP

ecological data, Forest Inventory and Analysis (FIA) nationwide inventory from USDA Forest Service, proprietary industrial data, various GIS data available from state sources, published and unpublished research

Simulation tool: Options, a forest estate planning and modeling application

Adjacency/green-up constraints spatial restrictions in harvesting stands

bordering previously harvested areas allow some length of time for establishing a

new stand before the adjacent stand can be harvested

may introduce additional costs or loses caused by non-optimal harvest timings

impact on ecological and social functions of forests

help in preventing the forest from windthrows

Adjacency effects depend on…

allowable size of forest management blocks before an adjacency rule is activated

length of time an adjacency rule is in effect once it is activated

the parameter(s) used to determine when an adjacency rule has been satisfied (e.g., average height of dominant trees)

the range of silvicultural and harvesting treatments subject to adjacency rules

Adjacency effects depend on…

existence of additional constraints or regulations affecting the availability of forest stands for harvest (e.g., SMZs, RBBs, etc)

growth rates of newly regenerated or treated stands relative to the adjacency rule (note that if time is being used, then growth rates are immaterial)

size of the landbase

Assumptions

Base (“no action”) scenario: Constant landbase Current management practices and

trends in their transition Constant harvesting of 42 million m3/year Constant extent of intensive management

(current 30% of all pine plantations)

Assumptions Modifies base (“realistic”) scenario Constant landbase Current management practices and

trends in their transition Gradually increasing cut (+50%/50y, from

42 to 63 million m3/year in 2050) Increasing extent of IMP (30% rate of

conversion)

Assumptions Rule 1: neighboring stand can be

harvested when a newly established stand reaches the average height of 1.5 meters

Rule 2: regeneration has to be at least 2 meters high, but harvesting cannot take place earlier than 3 years after harvesting of the adjacent stand

Results

Base scenario, Rule 1, Rule 2: Volume available for harvesting

(sum of volume of all stands that reached or passed their maturity age)

Volume cut Extent of deferred area and volume

Base (“no action”) scenario

Base

Rule 1

Rule 2

Deferred areaArea

0

5

10

15

20

2000 2010 2020 2030 2040 2050

Year

% Rule 1

Rule 2

Deferred volumeVolume

0

5

10

15

20

25

30

35

2000 2010 2020 2030 2040 2050

Year

% Rule 1

Rule 2

Modifies base (“realistic”) scenario

Base

Rule 1

Rule 2

Deferred areaArea

0

5

10

15

20

25

2000 2010 2020 2030 2040 2050

Year

%Rule 1

Rule 2

Deferred volumeVolume

0

5

10

15

20

25

30

35

2000 2010 2020 2030 2040 2050

Year

%Rule 1

Rule 2

Discussion harvesting and constraints pushed

harder – more noticeable impact small impact for large areas,

especially when harvesting is way below the resource capacity,

large impact on smaller areas, especially if other spatial constraints are considered

Discussion can affect wood availability in the

future, however this depends on the assumed rules

effects can be significant especially with combination with other factors

impact on particular owners, their management and additional costs is can be significant in any case

Thank you!