Mixed oak Hickory Silvicultural systems

Transcription

1 Mixed oak Hickory Silvicultural systems Mark S. Ashton Morris K. Jesup Professor of Silviculture and Forest Ecology / Director of School Forests Yale University Jeffrey S. Ward Chief Scientist Station Forester Connecticut Agricultural Experiment Station Photo: Emery Gluck Laws of oak silviculture Loftis (2004) 1. The presence of competitive sources of oak regeneration (advanced regen / stump sprouts). 2. Timely, sufficient release of these oak regeneration sources. 2a. timely, sufficient release of oaks throughout stand development 1

2 100% Most value is on few trees % stand value (mean=$4,205) 80% 60% 40% 20% 0% Number of trees per acre Idea Gary Miller USDA FS NRS How and when you can influence stand dynamics Seedling stands Sapling stands Pole / sawtimber stands Regenerating stands 2

3 How and when you can influence stand dynamics Seedling stands Sapling stands Pole / sawtimber stands Regenerating stands Oak Maple Birch Birch Oak Maple Birch Oak JP Maple 3

4 Consider burning in young clearcuts Oak Maple Birch Birch Oak Maple Birch Oak Maple Height of new sprouts similar, Oaks are now free-to-grow Root/shoot 4

5 Oak Maple Oak Birch Maple Oak Maple Free-to-grow oak seedlings have a better chance of persisting through canopy closure, and therefore, form part of the mature stand Oak density (n/ha) Oak Burned Gypsy moth Minor Stand age In 1932, a hot fire in a sapling stand doubled amount of oak 60 years later Maple density (n/ha) Maple Burned Gypsy moth Minor Birch density (n/ha) Burned Gypsy moth Minor Stand age Stand age Old Series- Medium sites Birch 5

6 Browse slows growth just enough Height of tallest sprout (feet) Oak stump sprouts Caged No protection Years since harvest 6

7 100% A little browse damage Stumps with free-to-grow oak sprouts 80% 60% 40% 20% FTG sprouts Dead None >5 0% Caged Browse protection type No protection How and when you can influence stand dynamics Seedling stands Sapling stands Pole / sawtimber stands Regenerating stands 7

8 Canopy closure begins the crucial period of rapid self-thinning Most codominant & intermediate sapling oaks regress or die Upland oaks without release C D C i C i C C C 8

9 Many, if not most, codominant and intermediate oak saplings will not remain in the upper canopy of unmanaged sapling stands except on drier sites. Crop tree release 9

10 Codominants more bang for your buck Upland oaks; single release Precommercial crop tree release provides an opportunity to increase the proportion of upper canopy oaks in pole stands. 10

11 10 But no real growth increase without a 2 nd release Mean crop tree diameter (inches) Second release Number of crop tree releases None Once Twice Years since release Stem Quality Precommercial release had no effect on: Tree form (stem taper) % of trees with stem defect (lean, sweep, crook) Presence or number of branches on lower bole Proportion of trees without forks or large branches (>5 cm, 2 ) for the first two sawlogs (10 m or 32 ft) 11

12 How and when you can influence stand dynamics Seedling stands Sapling stands Pole / sawtimber stands Regenerating stands Stand growth (basal area, volume) relatively constant over a wide range of stocking 12

13 Pole/sawtimber crop tree release (CHFC XV) 18-yr diameter growth increase 5.0 Crop tree Control Diameter growth (inches) < Initial diameter class (inches) NUoakCrop.xlsx 13

14 Mature sawtimber crop tree release Tunxis Dump Study Area 2-5 acre buffer Uncut 50x50 m (0.62 ac) B-level 14

15 120% Stocking reduced to B-level Stocking 100% 80% 60% Pole-harvested Saw-harvested Pole-residual Saw-residual 40% 20% 0% Uncut B-level Crop tree Management prescription 15

16 Crop tree release results in a mosaic stand Individual tree response 16

17 Increased growth of large oak 1.5 Croptree B-level Uncut 5-year diameter growth Initial diameter class (inches) Org4dataDBH.xlsx Individual tree response Oaks up to at least 26 DBH respond Crop tree > B-level > unmanaged Growth increased with increased release Growth increase for 5+ years * 66 cm 17

18 Stand level response Net basal area change (ft^2/acre) Sawtimber basal area growth Sawtimber (> 11 inches dbh) Croptree B-level Uncut Years since release 18

19 Release increased pole basal area Net basal area change (ft^2/acre) Poletimber (4-11 inches dbh) Croptree B-level Uncut Problem Years since release Cutting methods study (NJAF) 19

20 Shelterwood Multi-aged crop tree AKA Coppice with standards Volume growth maintained (18-yrs) 20

21 Stand level response Sawtimber basal area growth only slightly decreased by management. Because largest oaks left after harvest, likely that board-foot volume growth unchanged by management. Poletimber basal area growth greatly increased by harvesting. How and when you can influence stand dynamics Seedling stands Sapling stands Pole / sawtimber stands Regenerating stands 21

22 Advanced regeneration is key for Oak, but also for red maple Larger and older stumps sprout less often 100% Upland oak Probability of stump sprouting 80% 60% 40% 20% Red maple Black birch Sugar maple 0% Preharvest diameter of breast height (inches) 22

23 Management options >5 Even-aged management Favors oaks, pine, aspens, cherry 23

24 Uneven-aged management Favors maples, beech, birch, hemlock Assumptions What is established on site at time of crown closure (8-12 years) is what you have to work with. What is in upper canopy at time of crown closure is what will dominate site for decades to come* *except grey birch and pin cherry *can be modified with early cleaning 24

25 Therefore: Failure is defined as inadequate regeneration of species you want after final harvest to have a fully stocked stand at canopy closure. BUT you will eventually have some trees on the site, just maybe not those you want and it might take a couple of decades. Causes of Regeneration Failure Inadequate advanced regeneration No seed source (light seeded, seedbank) Site problems Animal damage Interference from competing vegetation 25

26 Competitive regeneration Advanced regeneration essential Oak, maple, hickory, white pine Can seed in after harvest Birch, aspen, ash, yellow-poplar, black cherry* Excellent advanced regeneration Oak, maple, hickory, white pine 26

27 Inadequate advanced regeneration Oak, maple, hickory, white pine Inadequate advanced regeneration Oak, maple, hickory, white pine - Assess stand before final harvest. - If inadequate regen present, determine cause* and take action. - Assess stand again after several years. *Low light, deer browse, competition 27

28 No seed source (light seeded, seedbank) Birch, aspen, ash, yellow-poplar, black cherry Wind disseminated Seeds can travel hundreds of yards, but most stay fairly close. Seedbank Either it s there or it isn t. Cherries, sassafras, pepperidge, dogwood Site problems Water table Heavy duff Skeletal soils 28

29 Ralph Nyland 50 years distilled 29

30 Limiting browse damage Increased hunting can be effective sometimes and need to lower density to 12/mile 2 or lower Deer impacts vary by available forage Brose et al (2008) USDA FS GTR-NRS-33 30

31 Shoot the deer 17-year-old sugar maples Animal damage Mississippi State Univ. Purdue University 31

32 Influence of deer and harvesting on oak regeneration Oak regen depressed by deer browsing Shelterwood Not hunted (n=7) Overstory removal (clearcut) 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 32

33 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 40 deer/km 2 (104 deer/mile 2 ) 33

34 Limiting browse damage Fencing?? Must be at least 8-feet tall & Expensive $$$* $8,000 for 25 acres in PA, $320/acre For the ~$8,000 cost to fence 25-acres, a sharpshooter could control deer on 640 acres 34

35 Poison the Beech Interference from non-native invasives Stiltgrass Buckthorn Mile-a-minute Barberry Bittersweet 35

36 Interference from natives Huckleberry Hay-scented fern Beech Laurel 36

37 Manage the light Credit: Mark Bird Credit: Emery Gluck Regenerating Oak-Hickory Forests 37

38 A map of all 35 irregular shelterwoods, group selection and hybrid systems and 15 understory reserves on the 7860 acre Yale-Myers Research and Demonstration Forest over a twenty five year span Silvicultural Implications: Ridge Hold onto structure, build up regeneration Midslope Dominant site type, most challenging Black birch competition Follow up treatments Valley Opportunistic, open up canopy to favor oak over shade tolerants 38

39 Irregular seed tree - shelterwoods Valley/toe-slope midslope ridge Patch group single-tree selection Valley/toe-slope midslope ridge Open areas Canopy (mid-tolerants Shade-tolerants reserves) 39

40 Application: Irregular Shelterwoods General principles for securing advance regeneration of oak and hickory 1. Emulating episodic disturbance regimes; 2. initial floristics; 3. release; 4. focus on partial shade-intolerant canopy dominants Topographic position Prescription Reserves Bottom-slope Irregular shelterwood/seed-tree Group reserves reduce edge Valley spacing; >20 dbh (sugar maple/ hemlock/beech) Acute >10 y on est. treatment Opportunistic Mid-slope Single-tree reserves (hemlock/spruce/ sugar maple /beech) 4-8 dbh; per ac Chronic Ridge Irregular shelterwood Single-tree reserves spacing; >15 dbh (oak/ hickory) 5-10 y on est. treatment 6-10 dbh; per ac Building Yale-Myers Prescription Handbook, Unpubl. manuscript Conservation - Reserves and Structures Soft mast - Red maple, cherry Hard mast hickory and white oak Den and structural islands wolf trees Snags and cavity trees all species except birch - >10 /ac >10dbh Future snags and cavities/bark - red maple, hickory Structure groups and individuals hemlock Other species basswood, yellow birch white oak, tulip poplar, cherry Wildlife activity nest platforms, woodpecker holes Economic Reserves Sugar maple form and size strong epinastic growth and deep crown (not more that 10/ac) Red oak no sign of epicormics, ski-tracks and potential vase shaped crown expansion 40

41 Valley mesic toeslope till spacing - 20 dbh Opportunistic and heavy-handed Hold less structure and in groups to reduce edge 41

42 Midslope till spacing dbh Need cleaning from black birch at about 5-8 years Ridge thin to bedrock till spacing; 15 = dbh Can hold on to more structure and build oak regeneration 42

43 Breeding Bird Richness in Shelterwoods Duguid et al., 2016 Breeding Birds in Shelterwoods 1 early initiation (1-7 y) 2 late initiation (8-14 y) 3 early stem exclusion (15-21 y) 4 mature (> 80 y) Duguid et al.,

44 Breeding Birds in Shelterwoods Duguid et al., 2016 Amphibians/Reptiles in Shelterwoods EI (3-6y) LI (9-16) SE (18-25)M n-sample size Red backed salamander (# per 4 m 2 plot) Eastern newt Garter snake Mossman et al., Unpublished data 44

45 How and when you can influence stand dynamics Seedling stands Sapling stands Pole / sawtimber stands Regenerating stands 45

46 Growth increases with release 4.0 Oak sawtimber 5-yr diameter growth (cm) >=90 Degree of crown release (%) 0.45 /5-yr 46

47 Limiting browse damage Individual tree protection for enhancement plantings Forest management research 47