Rehabilitation of degraded hardwood stands notes from CT. Degraded stands: definition, extent and causes. What can you do?

Transcription

1 Rehabilitation of degraded hardwood stands notes from CT Jeffrey S. Ward, Station Forester Department of Forestry & Horticulture Connecticut Agricultural Experiment Station New Haven, Connecticut Degraded stands: definition, extent and causes What can you do? Whole stand vs. micro-stand approach Residual stems Sapling, poletimber, sawtimber Regeneration Degradation defined Thompson, I. D., M. R. Guariguata, K. Okabe, C. Bahamondez, R. Nasi, V. Heymell, and C. Sabogal An operational framework for defining and monitoring forest degradation. Ecology and Society 18(2): 2. Forest degradation is broadly defined as a reduction in the capacity of a forest to produce ecosystem services such as carbon storage and wood products as a result of anthropogenic and environmental changes. Degradation defined Thompson, I. D., M. R. Guariguata, K. Okabe, C. Bahamondez, R. Nasi, V. Heymell, and C. Sabogal An operational framework for defining and monitoring forest degradation. Ecology and Society 18(2): 2. Degradation defined Thompson, I. D., M. R. Guariguata, K. Okabe, C. Bahamondez, R. Nasi, V. Heymell, and C. Sabogal An operational framework for defining and monitoring forest degradation. Ecology and Society 18(2): 2. Forest degradation is broadly defined as a reduction in the capacity of a forest to produce ecosystem services such as carbon storage and wood products as a result of anthropogenic and environmental changes What is a poorly stocked stand? Below 6% (or 4%) on stand stocking chart Clatterbuck (26) 5ft^2/acre of AGS as threshold You know it when you see it 1

2 Poorly stocked stands how big a problem? 2, acres in CT and 6, acres in southern New England (11% of forested area in Connecticut). Three million acres in New England, NY, NJ and PA (16% of forested area). Another 7.5 million acres are one harvest away from becoming poorly stocked. Site problems High water table Heavy duff Skeletal soils Aug Voluntown Credit: Joel Stocker (UConn) 15-yr-old shelterwood 2

3 1% Most value is on few trees % stand value (mean=$4,25) 8% 6% 4% 2% % Number of trees per acre Idea Gary Miller USDA FS NRS Early warning signs of Diameter Limit Cutting / Selection harvests Hutnik (1958) WV, Trimble (1961) WV, Blum and Filip (1963) NH, Hart (1964) ME Decreased stand growth / poor-quality residuals Ward (1983) OH Increased red maple, loss of oak Ezell (1992) MS low quality, slow growing residuals Strong (1995) WI Increased proportion residual culls and lower grade 1992 Northern hardwoods / mixed woods Selection harvests can be appropriate for stands with shade-tolerant valuable species However, selection harvests all to often slide over to the dark side of high-grading with only larger, economically valuable trees removed and no tending of smaller size classes to maintain diameter distribution 3

4 Stratified, second-growth forests Second growth forest history and origins: Gradual divergence N. red oak Black birch Red maple Should only be: Tending cuts (thinning) Regeneration cuts Ashton (217) Northeast Silviculture Institute Oliver (1978) Second growth forest history and origins: Abrupt divergence Northern red oak Hemlock Stratified Forests Midtolerant canopy (e.g., oak, cherry) Ashton (217) Northeast Silviculture Institute Kelty (1986) Shade tolerant subcanopy (e.g., red maple, beech) Stratified Forests Midtolerant canopy (e.g., oak, cherry) Shade tolerant subcanopy (e.g., red maple, beech) 4

5 After high-grading Cutting methods study un cut DiaLt Shelt MACT SilCC HiGrd un cut Ward et al. (25) NJAF Treatments Commercial clearcut (high- graded) All merchantable trees > 11 dbh were harvested. Diameter Limit Removal of cull trees; Oak, sugar maple, ash (21 IOH, 17 BP, 16 NM); Other species (16 IOH, 14 BP and NM) MACT (multi-aged crop tree management) 5-6 crop trees per acre. One-fifth of crop trees cut every 15 years, and an equal number of new crop-trees selected. All other poles cut when crop trees removed. Shelterwood Marked to remove 5% of basal area and 5% of upper canopy. Board-foot volume growth High-grading loss of oak poletimber Net board-foot growth (bf/acre/year) A A A A Other Birch Maple White oaks Red oaks B Uncut DiamLt Shelt MACT HiGrad Cutting methods Basal area (ft 2 /acre) after second cutting cycle 1% 75% 5% 25% Other Birch Maple White oaks Red oaks % Preserve MACT DiamLt HiGrade Residual stand - Poletimber Cutting methods 5

6 15-yr-old shelterwood (LG) 15-yr-old clearcut (LG) Degraded stands: definition, extent and causes What can you do? Whole stand vs. micro-stand approach Residual stems Sapling, poletimber, sawtimber Regeneration 17-yr-old diameter limit (NM) Rehabilitating poorly stocked stands Basal area I Diameter High-graded - Where to start? Basal area = cross-sectional Area (pi * radius squared) at 4.5 feet. Biomass (volume) increases linearly with basal area. 4.5 feet = Breast Height thus, DBH Charles Island - 75 deer/sq. mile.25 Basal area II Sixteen 1-inch trees has same BASAL AREA has one 4-inch tree 4. UGS vs. AGS UGS Unacceptable growing stock Poor form (severe crook, sweep, low fork) Poor health (dying or dead) High cull (>4% internal decay or defect) Undesirable species (local market dependent) AGS Acceptable growing stock Not an UGS CAES- Plant Science Day 21-1 th Anniversary 6

7 What is a poorly stocked stand? Below 6% (or 4%) on stand stocking chart Stands Clatterbuck (26) 5ft^2/acre of AGS as threshold Stand level approach High-graded / poorly stock stands often have patchy structure Pre-prescription inventories cost $$$, prescriptions cost $$$, and poorly-stocked stands have very low value. Pretreatment basal area Very irregular stand structure Ehlich Preserve (%) UGS AGS Ehli17 Ehli1 Ehli15 Ehli5 Ehli1 Ehli18 Ehli13 Ehli11 Ehli8 Ehli14 Ehli12 Ehli16 Ehli6 Ehli7 Ehli3 Ehli4 Ehli2 Ehli9 Pretreatment basal area Bass Road Preserve (6%) UGS AGS Pretreatment basal area East River Preserve (56%) UGS AGS Guil9 Guil3 Guil11 Guil1 Guil4 Guil7 Guil6 Guil1 Guil16 Guil13 Guil17 Guil12 Guil18 Guil15 Guil8 Guil14 Guil5 Guil2 Pretreatment basal area Rebekah's Hill (43%) UGS AGS Rebe2 Rebe26 Rebe24 Rebe22 Rebe27 Rebe16 Rebe21 Rebe25 Rebe23 Rebe5 Rebe9 Rebe1 Rebe7 Rebe15 Rebe19 Rebe14 Rebe11 Rebe28 Rebe1 Rebe3 Rebe8 Rebe4 Rebe12 Rebe2 Rebe17 Rebe6 Rebe18 Rebe13 Clatterbuck (26) 5ft^2/acre of AGS as threshold also good overview 7

8 Micro-stands Lussier and Meek (28) Decisions made by harvester operator Train Trust, but verify Forest Rehabilitation: A micro-stand approach Rehabilitation Cage studies Rosenberg - Rebekah s Hill 1Poles Control 2Poles Control 3Poles Low 4Poles Control 52 aged High 6Poles Low 7Poles Low 8Poles High 92 aged Low 1 Poles High Poles High 12 Poles High 13 Poles High 14 Poles Low 15 Poles Low 16 Poles Low 17 Poles Control 18 Poles Control 19 Poles Control aged Control 21 2 aged High 22 Initiate High 23 2 aged Low 24 2 aged Low 25 2 aged High 26 2 aged Control 27 2 aged Control 28 Poles High

9 Plot layout Low intensity 2 m 2 m 2 x 2 m plots ~1/1 acre plots ~3 ft radius 1/1 acre plots, ~3 ft radius High intensity High-intensity, two-aged plot Low-intensity, Poletimber plot Regeneration, High(l) and Low (r) 9

10 Degraded stands: definition, extent and causes We removed most of UGS 6 What can you do? Whole stand vs. micro-stand approach Residual stems Sapling, poletimber, sawtimber Regeneration Stand basal area (sq.ft. per acre) UGS (unacceptable growing stock) AGS (acceptable growing stock) Initial Residual Release improved stand composition Pre-treatment Post-treatment Release increased pole and sawtimber diameter growth 1.25 B UGS Oak Birch Other UGS Other Oak 4-yr diameter growth (inches) A B B A B A AB B Birch. No PartialFull No PartialFull No PartialFull Maple Oak Hickory Maple Oak Hickory Release increased stand AGS growth relative to UGSs 8 4-year basal area growth (sq.ft. per acre) AB AGS (Treated) C UGS (Treated) B AGS (Control) A UGS (Control) 1

11 3. Oak sapling growth - I Sapling growth Oak sapling growth - II 3. Sapling growth Diameter (inches) Diameter (inches) Oak - High Oak - Control Years since treatment Oak - Low Oak - Control Years since treatment Diameter (inches) Oak sapling growth - III 3. Sapling growth Oak - High Oak - Low Oak - Control Pine - Control Birch - Control Years since treatment wo/release Dominant 71% 25-yr UCP Codominant 27% SpeciesCCTR.xlsx Intermediate 6% Many, if not most, codominant and intermediate oak saplings will NOT remain in the upper canopy of unmanaged sapling stands except on drier sites. Precommercial crop tree release (PCTR) increases the proportion of upper canopy oaks in pole stands. Pole/sawtimber crop tree release (CHFC XV) PCTR 25-yr Upper canopy persistence Dominant 77% Codominant 56% Intermediate 21% 71, 27,6 SpeciesCCTR.xlsx 11

12 18-yr diameter growth increase 5. Crop tree Control Degraded stands: definition, extent and causes Diameter growth (inches) < Initial diameter class (inches) What can you do? Whole stand vs. micro-stand approach Sapling Residual stems Sapling, poletimber, sawtimber Regeneration NUoakCrop.xlsx Degraded stands: definition, extent and causes Ralph Nyland 5 years distilled What can you do? Whole stand vs. micro-stand approach Residual stems Sapling, poletimber, sawtimber Regeneration Limiting browse damage Deer impacts vary by available forage Increased hunting can be effective sometimes and need to lower density to 12/mile 2 or lower Brose et al (28) USDA FS GTR-NRS-33 12

13 Shoot the deer Animal damage 17-year-old sugar maples Mississippi State Univ. Purdue University Influence of deer and harvesting Oak regen depressed by deer browsing on oak regeneration Shelterwood Overstory removal (clearcut) Not hunted (n=7) Not hunted (n=15) Estimated FTG oaks (n/acre) Hunted (n=9) Hunted (n=13) Green / blue good Yellow / orange ok Red / purple bad Black nothing there Limiting browse damage Large harvest areas may disperse browse damage Protect from browse damage 11-yr-old with no protection 6-yr-old with protection 4 deer/km 2 (14 deer/mile 2 ) 13

14 Limiting browse damage For the ~$8, cost to fence 25-acres, a sharpshooter could control deer on 64 acres Fencing?? Must be at least 8-feet tall & Expensive $$$* $8, for 25 acres in PA, $32/acre Poison the Beech Interference from non-native invasives Stiltgrass Mile-a-minute Bittersweet Buckthorn Barberry Interference from natives Huckleberry Hay-scented fern Beech Laurel 14

15 Shoot the deer, poison the interference Manage the light Outside exclosure Inside exclosure 2, (e) > 3 ft tall I - untreated 2, (f) > 3 ft tall I1 - mowed Density (n/ac) 1,5 1, I3 - mowed then heat-treated twice Density (n/ac) 1,5 1, Growing seasons since treatment Growing seasons since treatment Credit: Mark Bird Credit: Emery Gluck Browse slows growth just enough Height of tallest sprout (feet) Oak stump sprouts Caged No protection Years since harvest Stumps with free-to-grow oak sprouts 1% 8% 6% 4% 2% A little browse damage % Caged FTG sprouts Dead None >5 No protection Browse protection type Degraded stands: definition, extent and causes What can you do? Whole stand vs. micro-stand approach Residual stems Sapling, poletimber, sawtimber Regeneration 15

16 Jeff Ward - CAES (23) jeffrey.ward@ct.gov Data collection 2 m Stems > 12.5 cm dbh (5 ) Species, diameter, crown class, UGS/AGS, pulpwood height, cubic foot cull 2 m Stems cm dbh Species, diameter, crown class Stems > 5 cm tall Species, height 16