1
INTRODUCTION TO FOREST INTRODUCTION TO FOREST REGENERATIONREGENERATION
Ralph D. Nyland
Distinguished Service Professor - SilvicultureDepartment of Forest and Natural Resources Management
SUNY College of Environmental and Forestry
Syracuse, NY 13210
Nyland - 2010 All rights reservedUse of all or parts of this permission prohibited
without express consent of Ralph D. Nyland
Background reading:
Chapter 4, in Nyland, R.D. 2002. Silviculture: Concepts and Applications.Waveland Press. Long Grove, IL. 2ed.
Sources cited:
Harper, J.L. 1977. Population Dynamics. Academic Press. NY.
Maynard, CA., R.P. Overton, and L.D. Johnson. 1987. The silviculturist’s role in tree improvement in northern hardwoods. Pp. 35-46, in Managing Northern Hardwoods. R.D. Nyland (Ed.). SUNY Coll. Environ. Sci. and For.,Fac. For. Misc. Publ. No. 13 (ESF 87-002), Soc. Am. For. Publ. No. 87-03.
Nyland, R.D. 1998. Patterns of lodgepole pine regeneration following the 1988 Yellowstone fires. For. Ecol. & Manage. 111:23-33.
Roe, A.L., R.R. Alexander, and M.D. Andrews. 1970. Engelman spruce regeneration practices in theRocky Mountains. U.S. For. Serv. Prod. Res. Rpt. 115.
2
Acting definitively to influence the future … Erkki Okasnen
WHAT SILVICULTURISTS DO:
CONTROL
ESTABLISHMENT
DENSITY
COMPOSITIONFACILITATE
HARVESTING
MANAGEMENT
USE
PROTECT
SITES
TREES
SALVAGE
DEAD & DISEASED TREES AND STANDS
POTENTIAL MORTALITY & EXCESS TREES
… in regenerationand tending
3
... with plantations
At both large and small scales …
4
Or natural regeneration …
Uneven-aged
Even-aged
… one stand at a time
5
… gradually having a cumulative effect through time across a landscape
To promote regeneration …
1. Influence TIME when establishment occursand the PLACE
- schedule carefully the timing & nature of cuttings
- create new stands by seeding or planting if necessary
6
… with the time, place, and method that best satisfies a landowner’s objectives
To promote regeneration …
2. Influence COMPOSITION of new stands
- alter or create favorable seedbeds & stand environment
- create new stands of wanted species, or enrich othersby artificial means
7
... by regulating the intensity of cutting
... by influencing the character of seedbeds
... by scheduling the time and placement of cuttings
... by seeding and planting where deemed useful
To promote regeneration …
3) SUPPLEMENT naturally occurring regeneration,or REPLACE it
- enrichment- substitution- fortification
… by artificial means
8
... by planting or seedingJ.D. Irving, LTD - 2000
... to make forests more valuable
... for an owner
9
The role of cutting (e.g., timber harvesting)...
... implement the reproduction methodreproduction method
Create voids
when wanted ...
10
… to initiatethe regeneration
process
At other times ...
... we keep stands DENSER
… when we don’t want regeneration
11
... particularly among immature stands
So that all the growth potential
“goes” on the existing trees …
12
Throughout the regeneration process you must:
- know the objectivesknow the objectives
- deliberately identifydeliberately identify the potential obstacles to success
- select an appropriate speciesselect an appropriate species for the site and objectives
- plan and implementplan and implement the necessary preparatorytreatments and anti-risk counter-measures
- identify a stocking and arrangementidentify a stocking and arrangement to enhance the use, tending, and harvest that will eventually follow
- implement the planimplement the plan using cost-effective methods
All to insure that the outcomeprovides appropriate rewardsprovides appropriate rewardsto the landowner …
13
... and no surprises
So we insist upon seed or planting stock from origins:
- fitted to the needs- of desirable phenotypes- with a capacity to survive and grow successfully on
the site- at least as good in sought-after qualities as the old stand, or that natural regeneration would provide
14
Appropriate species …… good seed source
... at adequate stocking
We seek to satisfy these objectives bygaining controlcontrol over forest stand regeneration …
… and the environmental conditions at the time when regeneration occurs
15
We identifyidentify and managemanage the risk of being
overwhelmed by forces of disaster
Managing the risks …
Roe et al. 1970
… by integrative thinking
16
… with a high chance of failure IFIF
one leg of the regeneration triangle
not suitable or gets out of control
We cannot entirelycontrol these
BUT BUT ……
17
– EXTERNALEXTERNAL forces like …
• animal feeding
• disease
• insect attack
• fire
… we try to protect against these
Two groups of environmental factors …
… guarding against this
Glenwood Springs, CO -- June 2002
18
– INTERNALINTERNAL site factors like…
• temperature• moisture• nutrients• light
… we want neither too much or too little
Two groups of environmental factors …
… controlling conditions by even unusual means
Like using shade to reduce transpirationfrom young and sensitive seedlings …
19
By actively managing the risk that these present …
… and turning risk into OPPORTUNITYOPPORTUNITY
... and regeneration success
20
SOURCES OF REGENERATION
– seed– seedlings
SEX
UA
L
… seeds carry the genetic traits of their parent treesNissen 2002
21
… so do the seedlings that come from them
… most seed falls close to the parent tree
... especially in closed stands
And seed dispersal counts too …
Nyland 1998
22
Then what happens to the seeds …
A reproduction methodprovides the stimulus …
… to get good numbers of well-distributed seedlings of desired species
23
… to initiate and establish a new age class
… by leaving adequate seed-producingtrees in natural stands
… so we also need to controlcontrol seed dispersal and storageto insure regeneration success
24
… or delivering it to a site by planting or seeding
Georgia Pacific, Maine
– sprouts / shoots / cuttings / suckers
– graftings
– plantlets from tissue cultureVE
GE
TA
TIV
E
Another source …
25
… beech root sucker
… or with coppice methodof natural regeneration
26
… originating as root suckers following clearfelling of aspen
How different sources fit into different regeneration programs …
Natural regeneration
seed advance seedlingssprouts / suckers / shoots
Artificial regeneration
seed nursery seedlings cuttings (vegetative)plantletsgraftings
Mostly for treeimprovement programs
27
... in this case by tissue cultureMaynard 1985
Or like ArborGen southern pine plantlets for production use …
ArborGen 2007
28
• NATURAL– least costly (though not without costs)
– species adapted to the site (though not necessarily the most valuable ones)
ADVANTAGES OF EACH
… though not without cost
29
ADVANTAGES OF EACH
• ARTIFICIAL (CONTROLCONTROL)
– direct controlcontrol over genotypes, species, and placement
– complete controlcontrol over timing– can repeat if necessary
… with high costs togain “total” control
J.D. Irving, LTD - 2000
30
ADVANTAGES OF EACH
• MIXED
– cost intermediate ifif done correctly–– somesome influence over genotypes, species, and
placement– excellent in salvaging a hopeless situation
… so take it all into account
Perhaps like this …
31
DISADVANTAGES OF EACH
• NATURAL– get variation in stocking, species, and time– only existing genotypes and species regenerate– at mercy of natural forces
... we work hard to control these– must wait for adequate seed crops
… unless properly controlledcontrolled, it may give poor results
32
DISADVANTAGES OF EACH
• ARTIFICIAL
–– expensiveexpensive (must repay with interest)
– impractical in remote areas…except for broadcast seeding
– major logistical effort
… balancing the costs against the gains
Great Northern Paper Co.
33
DISADVANTAGES OF EACH
• MIXED– often must control naturally occurring plants
… interference– if need to reinforce, may find unsuitable
environment
But often beneficial if done correctly …
34
... artificial
... naturalSo what to do …
Selecting between natural and artificial methods often means assessing …
AvailabilityAvailability of adequate seed of a suitable species and of good genetic quality
AssuranceAssurance of a suitable and reliable means for seed dispersal, or spread of vegetative parts
PotentialsPotentials for having a suitable seedbed at the appropriate time
Likelihood Likelihood of having available conditions essential to support initial post-establishment growth for the new seedlings
35
… and how to best serve a landowner’s objectives
And don’t forget your genes ...
36
BASE-LEVEL TREE IMPROVEMENT PROGRAMS
Base leveltree improvement
… practical silviculture fits in here
37
BASE-LEVEL TREE IMPROVEMENT PROGRAMS …
- careful selection of seed sources
- artificial regeneration to establish an age class (including
enriching and supplementing natural regeneration)
- timber stand improvement (in tending)
- integrated pest management to safeguard the growing stock
- skillful use of appropriate reproduction methods
... ways that foresters influence the genetic constitutionof forest stands dailydaily
… by favoring and regenerating good phenotypes
38
But always remember ...
Artificial regeneration commits a landowner to a long-term investment of considerable magnitude …
…so landowners MUSTMUST have assurance thatthe new stand will develop well under localconditions
So we insist on seed or planting stock from origins:
- fitted to the needs- of desirable phenotypes- with a capacity to survive and grow successful on
the site- at least as good in sought-after qualities as the old stand, or that natural regeneration would provide
39
… at least as good
… and hopefully better
… to get the desired responseSilviculture manages all these factors …
Nissen 2010