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1
THE SILVICULTURAL SYSTEMTHE SILVICULTURAL SYSTEM
Ralph D. Nyland
Distinguished Service Professor - Silviculture
Department of Forest and Natural Resources ManagementSUNY College of Environmental Science and Forestry
Syracuse, NY 13210
Nyland - 2010All rights reserved
Use of all or parts of this permission prohibitedwithout express consent of Ralph D. Nyland
Background reading:
Chapter 2, in Nyland, R.D. 2002. Silviculture: Concepts and Applications.Waveland Press. Long Grove, IL 2ed.
Sources cited:
Ford-Robertson, F.C. (Ed.). 1971, Terminology of Forest Science, Technology, Practice and Products. Multi-lingual For. Terminol. Ser. No. 1, Soc. Am. For. Wash., DC.
Helms, J.A. 1998. The Dictionary of Forestry. Soc. Am. For. Bethesda, MD.
Hummell, S.S. 2006. Seeing the bigger picture: Landscape silviculture may offer comparable solutions to conflicting objectives. US For. Serv., Pacific NW Res. Stn., Science Findings 85.
Koten, D.E. 1994 Lecture notes. Faculty of Forestry, SUNY Coll. environ. Sci., and For., Syracuse, NY.
Nyland, R.D., C.C. Larson, and H.L. Shirley. 1983. Forestry and Its Career Opportunities. McGraw-Hill Book Co., NY. 4ed.
Stone, EL. 1975. Soil and man’s use of forest land. In pp. 1-9, Forest Soils and Forest Land Management. B. Bewrnier and C.H. Winget (Eds.). Laval Univ. Press. Ste-Foy, QU.
Urban, D.L., R.V. O’Neill, and H.H. Shugart. 1987. Landscape ecology: A hierarcial perspective can help scientists understand spatial patterns. Biosci. 37(2):119-127.
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SILVICULTURE ...
… the methods for establishingestablishing and maintainingmaintaininghealthy communities of trees and other vegetation
……. that have value to people. that have value to people
… whatever the values
3
What silviculturists do ...
CONTROLCONTROL – establishment, composition,structure, and growth
FACILITATE – harvesting, management, and use
PROTECT – sites and trees
SALVAGE – dead and diseased trees, andpotential mortality
... controlling natural patterns of stand development to favor a landowner
4
SILVICULTURE
works with standsstands
STANDSTAND
A community of trees sufficiently uniform incomposition, constitution, age, spatial arrangementsite quality, or other conditions that distinguish it …
… so forming a silvicultural or management entity
After Ford-Robertson 1971, Helms 1998
5
So silviculture deals with stands …
…… homogeneous in some condition or characteristichomogeneous in some condition or characteristic
Treating one stand at a time …
… the silviculture
6
Easily identified on the ground …
… managed as individual units to enhance the desired valuesUS For. Serv.
7
… each according to a unique planAfter US For. Serv.
FOREST MANAGEMENT …
… deals with the collection of stands that comprise a forest
… or some other management unit
8
To make the whole forest more useful …
Integrating silviculture across an entire forest …
… the forest management
9
Like this ... … across time and space
Forest management ...
… to serve the interests of people
10
After Urban et al. 1987
Even thinking about the effects at a landscape scale …
11
… integrated acrossa compartment
… and throughouta forest
12
… always thinking aboutthe landscape
… with important influences coming from outside toaffect our options for managing stands and forests
13
… and others of the stand and forest dictatingwhat we can contribute to the larger area
Remember …
Hummel (2006) calls this …
… LANDSCAPE SILVICULTURELANDSCAPE SILVICULTURE
... developing prescriptions for individual stands, but evaluating them collectively based onobjectives for the landscape as a whole
14
How to do this ...
... the silviculture
THE SILVICULTURAL SYSTEMTHE SILVICULTURAL SYSTEM ...
... the plan for managing a stand over the long run
... the way we control, facilitate, protect, andsalvage in a stand
15
To control conditions and enhance the desired values …
THE SILVICULTURAL PLAN …
… the end point of a deliberate problemsolving process
… that starts with the objectives for management
16
THE PROBLEM SOLVING PROCESS:
1. Determine the landowner’s objectives2. Evaluate existing stand conditions
3. Identify the options
4. Quantify the likely outcome of each one
5. Drop unsuitable options
6. Explain the viable alternatives
7. Help the landowner decide
8. Implement the prescription
9. Evaluate the results
REMEMBER -
Learn the objectives …
… the rest will follow from
your thoughtfulness and creativity
17
… for a desirable outcome
So what does a system involve?
18
ALL SYSTEMS HAVE THREE COMPONENTSafter Nyland et al. 1983
Harvest… a means to
So what does a system involve?
Nyland 2002
SILVICULTURE SEPARATES FORESTRY FROM EXPLOITATION
Continuity over time Sustained values
Requiring all the critical parts …
19
The systems differ for three broad groups of stands …
(Definitions follow Helms 1998, Nyland 2002)
EVENEVEN--AGEDAGED
A community of trees having no or onlysmall differences in ages …
… by convention with a spread of ages not exceeding 20% of the rotation length
20
ROTATION …
… the planned number of years betweenformation of a stand (even-aged) and its final cutting (regeneration) at a specified degree of maturity
Starting with young ones …
21
… getting older
… and finally mature
22
… with a clear pattern of development through time… within a single stand
Aging
… and in each stand across a forest
23
All trees in a stand regenerated at the same time …… all developing to maturity together
… all coming of age at the same time
So …
Even-agedlodgepole pine
24
The silvicultural system for eveneven--agedaged stands
SEPA
RA
TE
DIN
TIM
E
One kind ofeven-aged reproductionmethod
25
... giving rise to a new even-aged community
... with eventual tending (e.g., thinning) to influence stand development
26
NEVER do all three at the same time
... for EVEN-aged silviculture
UNEVENUNEVEN--AGEDAGED
A community with trees that differmarkedly in their ages …
… by convention the spread of ages
exceeds 25% of the planned lifespan
for an age class
27
… each stand having trees of different ages
… including young trees
… intermixed with an older one
28
… and another
… and even another
29
… and often more
… all growing together in the same stand
30
… but only one reaching maturity at a time
… with ages and sizes interspersed across a stand
31
… and in stands across a forest
Parts regenerated at different times …… young, middle-aged, and old all present
… each comes of age at a different time
So …
32
Uneven-agedlodgepole pine
The silvicultural system for unevenuneven--agedaged stands
CO
NC
UR
RE
NT
33
SELECTION METHOD
... the uneven-aged
reproduction method
... coupledcoupled with tending of the threeor more age classes within a stand
34
ALWAYS do all three things with EACH entry
... for UNEVEN-aged silviculture
... concurrent treatments
TWOTWO--AGEDAGED
A community with trees of two distinct age classes …
… separated in age by more than 20% ofthe life span for each one
35
A young age class beneath older trees …
… through time the younger trees develop
36
… getting bigger and bigger
… we eventually remove the old trees and thin the remaining age class… to regenerate a new one
… and start again
37
… like this
Two distinct age classes present …… great difference in age between the two
… each comes of age at a different time
So …
38
Two-aged lodgepole pine
The silvicultural system for twotwo--agedaged stands
SOM
ET
IME
S A
LO
NE
USU
AL
LY
CO
NC
UR
RE
NT
39
REGENERATE a new age class ...
... while TENDING the other
... but may TEND separatelyat intermediate stages
1. We apply different KINDSKINDS of treatments orinterventions at different stages of standor age class development…
… and these occur in a logicalSEQUENCESEQUENCE
Conceptually, these designations imply at least twoimportant concepts:
40
2. To adequately control stand establishment,composition, and development (growth) …
… we must also plan for the properTIMINGTIMING of the treatments
… to insure the sought-after effects
TIMINGTIMING and SEQUENCESEQUENCE
as well as KINDKIND …
We do this through theSILVICULTURAL SYSTEMSILVICULTURAL SYSTEM
41
Pursuing the options …
… through silviculture
Financial factors often control intensity …
… the inputs of money, people, and other resources
But what about intensity?
42
… even when using efficient methods to implement the treatmentsJ.D. Irving, Ltd.
With intensity reflecting the inputs of funds, resources, and technology …
Few inputsAppreciable inputs
43
Each site can repay only certain levels of investments …
Domesticatedforest
And remember Stone’s advice ...
After Stone 1975
The better sites support a higher intensity of use …… and repay with higher returns
44
Careful planning can integrate
economic
and
ecologic factors
Look at one model …
... to highlight the challenges …
... and the concerns
45
CONCEPT
DRIVEN
INPU
TS
SILVICULTURE MERECUTTING
THE SILVICULTURE SURFACE ... a concept for management
Figure 2-7, in Nyland 2002
CONCEPT
DRIVEN
INPU
TS
SILVICULTURE MERECUTTING ECOLOGICALLYIRREVERSIBLE
After Nowak, Briggs, Germain, and Nyland 2000
CONCEPT
DRIVEN
INPU
TS
SILVICULTURE MERECUTTING ECOLOGICALLYIRREVERSIBLE
After Nowak, Briggs, Germain, and Nyland 2000
But the concept basis likely diminishes like this …
46
THE OBJECTIVE …
… to satisfy the economic benefits
but
… in an ecologically acceptable way
Economically viable ... … ecologically sound
47
CONCEPT
DRIVEN
INPU
TS
SILVICULTURE MERECUTTING ECOLOGICALLYIRREVERSIBLE
Yet economic constraints may limit actions …
.... keeping you in a limited box
So move as high on the silviculture surface
as financial and other institutional constraints
allow at the momentat the moment
48
But keep things off the slope …
CONCEPT
DRIVEN
INPU
TS
SILVICULTURE MERECUTTING ECOLOGICALLYIRREVERSIBLE
After Nowak, Briggs, Germain, and Nyland 2000
Exploitation often pushes stands over the edge …
49
Take care to cause no irreversible ecologic change …
insuring …
- trees after trees
- stable soils
- protected landforms
(e.g., intact drainages)
Silviculture makes the difference …