SILVICULTURE & WILDLIFE HABITAT MANAGEMENT

Transcription

1 SILVICULTURE & WILDLIFE HABITAT MANAGEMENT Ralph D. Nyland Department of Forest and Natural Resources Management SUNY College of Environmental Science and Forestry Syracuse, NY Nyland All rights reserved Use of all or parts of these class notes prohibited without express consent of Ralph D. Nyland Background reading: Various chapters in Nyland, R.D Silviculture: Concepts and Applications. Waveland Press. Long Grove, IL. 2ed. Sources cited: Healey, W.M Habitat characteristics of uneven-aged stands. Pp , in Managing Northern Hardwoods. R.D. Nyland (Ed.). SUNY Coll. Environ. Sci. and For., Fac. For. Misc. Publ. NO. 13 (ESF ), Soc. For. Publ. No Kenefic, L.S Quantitative Assessment of Wildlife Habitat in Uneven-aged Northern Hardwood Stands. M.Sc. Thesis. SUNY Coll. Environ. Sci. and For. Syracuse., NY. Nyland, R.D., D.G. Ray, R.D., Yanai, R.D. Briggs, L. Zhang, R.J. Cymbala, and M.J. Twery Early cohort development following even-aged reproduction method cutting sin New York northern hardwoods. Can. J. For. Res. 30: Patton, D.R Wildlife Habitat Relationships in Forested Ecosystems. Timber Press. Portland, OR. Soc. Am. For, Choices in Silviculture for American Forests. Soc. Am. For., Wash., DC. Thomas, J.W., R.G. Anderson, C. Maser, and E.L. Bull Snags. Pp , in Wildlife Habitats in Managed Forests: The Blue Mountains of Oregon and Washington. US For. Serv. Agric. Handbk

2 ... not a stretch Why wildlife management (a silviculturist s perspective) to enhance a wild animal population or the wildlife community in an area How commonly by altering habitat for the target species or a desired group of them 2

3 Habitat Quality (HQ) HQ = f ( Food + Cover + Water + Space )* we can readily manipulate food and cover and alter the expanse of a vegetation condition class * Patton 1992 By manipulating the vegetation... and that means SILVICULTURE! 3

4 ... but not just for game species Critical elements of wildlife habitat* HERBAGE forbs, sedges, grasses, ferns, and other herbaceous plants used for food and cover BROWSE buds, shoots, twigs, and leaves within 6feet of the ground and used as food COVER vegetation providing shelter from the elements or predators especially >1,000/ac of stems <1 inch dbh MAST fruits and seeds of trees, shrubs, and many understory plants CAVITIES holes and crevices in trees and used as shelter, dens, and nest sites DOWN WOODY DEBRIS logs, branches, and trees lying on the ground especially if 6 feet long and 6 inches in diameter at the small end *After Healy

5 for food and cover Critical elements of wildlife habitat* HERBAGE forbs, sedges, grasses, ferns, and other herbaceous plants used for food and cover BROWSE buds, shoots, twigs, and leaves within 6 feet of the ground and used as food COVER vegetation providing shelter from the elements or predators especially >1,000/ac of stems <1 inch dbh MAST fruits and seeds of trees, shrubs, and many understory plants CAVITIES holes and crevices in trees and logs and used as shelter, dens, and nest sites DOWN WOODY DEBRIS logs, branches, and trees lying on the ground especially if 6 feet long and 6 inches in diameter at the small end *After Healy

6 within reach as a source of food Critical elements of wildlife habitat* HERBAGE forbs, sedges, grasses, ferns, and other herbaceous plants used for food and cover BROWSE buds, shoots, twigs, and leaves within 6 feet of the ground and used as food COVER vegetation providing shelter from the elements or predators especially >1,000/ac of stems <1 inch dbh MAST fruits and seeds of trees, shrubs, and many understory plants CAVITIES holes and crevices in trees and ogs and used as shelter, dens, and nest sites DOWN WOODY DEBRIS logs, branches, and trees lying on the ground especially if 6 feet long and 6 inches in diameter at the small end *After Healy

7 like interfering with movement of larger predators Critical elements of wildlife habitat* HERBAGE forbs, sedges, grasses, ferns, and other herbaceous plants used for food and cover BROWSE buds, shoots, twigs, and leaves within 6 feet of the ground and used as food COVER vegetation providing shelter from the elements or predators especially >1,000/ac of stems <1 inch dbh MAST fruits and seeds of trees, shrubs, and many understory plants CAVITIES holes and crevices in trees and logs and used as shelter, dens, and nest sites DOWN WOODY DEBRIS logs, branches, and trees lying on the ground especially if 6 feet long and 6 inches in diameter at the small end *After Healy

8 both hard and soft mast for carbohydrates Critical elements of wildlife habitat* HERBAGE forbs, sedges, grasses, ferns, and other herbaceous plants used for food and cover BROWSE buds, shoots, twigs, and leaves within 6 feet of the ground and used as food COVER vegetation providing shelter from the elements or predators especially >1,000/ac of stems <1 inch dbh MAST fruits and seeds of trees, shrubs, and many understory plants CAVITIES holes and crevices in trees and logs and used as shelter, dens, and nest sites DOWN WOODY DEBRIS logs, branches, and trees lying on the ground especially if 6 feet long and 6 inches in diameter at the small end *After Healy

9 for nesting and protection Critical elements of wildlife habitat* HERBAGE forbs, sedges, grasses, ferns, and other herbaceous plants used for food and cover BROWSE buds, shoots, twigs, and leaves within 6 feet of the ground and used as food COVER vegetation providing shelter from the elements or predators especially >1,000/ac of stems <1 inch dbh MAST fruits and seeds of trees, shrubs, and many understory plants CAVITIES holes and crevices in trees and logs and used as shelter, dens, and nest sites DOWN WOODY DEBRIS logs, branches, and trees lying on the ground especially if 6 feet long and 6 inches in diameter at the small end *After Healy

10 that have a range of values through time As an example 10

11 BROWSE HERBAGE COVER MAST My basic requirements DEBRIS CAVITIES We can affect all of these through silviculture Triggering a transformation beneficial or not 11

12 Two important aspects of habitat... Vertical structural diversity (VSD) the dispersion of living branches from the ground to the top of the tallest trees in a stand After Patton 1992 Diversity along a vertical plane... due to the intermixing of height classes to form multiple canopy layers 12

13 Two important aspects of habitat... Vertical structural diversity (VSD) the dispersion of living branches from the ground to the top of the tallest trees in a stand Horizontal structural diversity (HSD) the spatial distribution and degree of interspersion of stands having different VSD across space Diversity on a horizontal plane After Patton

14 US Forest Service... due to structural differences across stands EDGE the interface between stands having distinctly different characteristics of VSD EDGE After Patton

15 NYS DEC... like this sharp and well-defined induced edge... even greater habitat diversity with different edges in close proximity 15

16 And the more edge... the greater the degree of HSD at a multi-stand or landscape level... due to the interspersion of stands having different structures 16

17 Contrasting even- and uneven-aged silviculture not if good or bad not if one acceptable and not rejecting the other But recognizing that the DIFFERENCES create habitats of DIFFERENT KINDS... and knowing we can often influence the MAGNITUDE of change as well Uneven-aged Even-aged 17

18 One option One option First, examine the even-aged systems... start with a mature stand starting with a financially mature stand fell the entire community at one time 18

19 establish a new cohort SAF eventually move on to an adjacent stand 19

20 ... produces an even-aged stand with limited VSD With a leafy canopy rising high above the ground Nissen 2010 and little foliage throughout the understory 20

21 Or another option do a seed cutting to an appropriate residual density 21

22 regenerate a new cohort SAF take off the overwood 22

23 TWO LAYERS FOR SHORT TIME... produces an even-aged stand with limited VSD but with a few years having a two-layered structure 23

24 With even-aged reproduction methods resulting in high initial stem density... Nyland et al that decreases through time e.g., at years of age 24

25 But high numbers 1 don t last long... Nyland et al Like this 5 years later for shelterwoods... with numbers 1 decreasing appreciably after years 25

26 and affording little cover (protection) by 30 years Afterward as the stand develops the canopy layer MOVES UP 26

27 Up to 8-10 years Early crown closure years years No / little understory years year to financial maturity UNTHINNED Some understory begins to form the development of even-aged stands creating little VSD 35years years 27

28 By about years in northern hardwoods Some understory begins to form... at about 80 years 28

29 Up to 8-10 years years years Thinned years 2 nd thinning years VSD likely to change THINNED for timber products reducing the crown canopy density through thinning in reproductively mature stands will LIKELY trigger some understory development at least temporarily INCRESING VSD... and notice the understory response by 10 years after thinning to 60% RD 29

30 Even-aged options The CHOICE The NATURAL way Treated to alter natural conditions (the development) to increase VSD This by nature or that by design 30

31 And what happens to some key habitat variables as a stand matures 30 years 60 years 31

32 taking several decades for seed production to begin in many species 32

33 Takes decades to develop After Patton

34 at 1 decade at 7 decades 34

35 Initially really high then dropping as the stand matures 35

36 Under intensive timber management schemes, we commonly eliminate cavity trees wildlife objectives often dictate different approaches 36

37 So how to adjust to enhance the habitat this or this see a difference in approach to accommodate wildlife objectives After Patton 1990 altering structure and character to diversify habitat 37

38 ... compared to even-aged silviculture for timber Selection system Now consider effects of uneven-aged silviculture... beginning condition 38

39 with concurrent regeneration and tending to balance the structure with regrowth of stocking and age class establishment during the cutting cycle 39

40 SAF repeated indefinitely through time Selection system stands Selection system stands have high VSD 40

41 like this Vertical Structural Diversity After Patton

42 with an interspersion of shrubs and trees having different heights Width in meters <1 Relative crown heights and widths for sugar maple trees in uneven-aged stands 42

43 Height in meters They overlap like this < cm 49 cm 28 cm 11 cm <3 cm Check the different uneven-aged stands... Single-tree selection system creates and maintains a HIGH degree of VSD 43

44 The reason for high VSD in selection system stands Height in meters < cm 49 cm 28 cm 11 cm <3 cm 44

45 ... single-tree selection Group selection system... creates and maintains a HIGH degree of VSD... and some micro-scale HSD as well 45

46 ... group selection system Patch-selection system creates and maintains a HIGH degree of VSD... and some added micro-scale HSD as well 46

47 ... patch-selection system We have choices... three viable selection systems 47

48 all resulting in structural stability And what happens to some key wildlife habitat variables after treatment... 48

49 adding considerable new coarse woody debris each cutting cycle 49

50 always having reproductively mature trees 50

51 continually some old and tall trees of large structure 51

52 Not much but increasing somewhat after each cutting After Patton

53 largely a limited number of shade-tolerant species (Unless special provisions) 53

54 and don t forget the cavities So how to adjust to enhance the habitat traditional diversified see the difference in approach to enhance wildlife habitat After Patton

55 altered to diversify the habitat elements Modified in nontraditional ways... to broaden the ecologic conditions 55

56 FEATURES OF EVEN-AGED SYSTEMS... - TREES INFLUENCED BY OTHERS OF SAME AGE - FAST EARLY GROWTH DUE TO FULL SUNLIGHT - EVEN COMPETITION ACROSS THE STAND - CHANGING ECOLOGICAL CONDITIONS AS STAND MATURES - BRANCHING INFLUENCED BY CROWDING - SPECIAL THINNING PROGRAMS NEEDED TO MAINTAIN VIGOR - COMPLETE REMOVAL AT END OF ROTATION - NEW REGENERATION MAY CONTAIN MANY SHADE-INTOLERANT TREES - REPEATED SELECTIVITY IN THINNING SHOULD UPGRADE GROWING STOCK QUALITY THROUGH TIME EVEN-AGED, WITHIN STAND -LOW VSD -NO HSD an even-aged community 56

57 FEATURES OF UNEVEN-AGED SYSTEMS... - TREES INFLUENCED BY OLDER TREES, OR HAVE DOMINATING POSITIONS DEPENDING ON AGE - EARLY SLOW GROWTH DUE TO PARTIAL SHADING - HETEROGENEOUS COMPETITION ACROSS STAND & THAT CHANGES AS TREES MATURE - ECOLOGICAL CONDITIONS NEVER CHANGE - BRANCHING INFLUENCED BY SPACING & TREE AGE - SPECIAL FELLING & SKIDDING NEEDED TO PROTECT RESIDUAL GROWING STOCK - NO COMPLETE REMOVAL - REGENERATION MOSTLY SHADE-TOLERANT SPECIES - CONTINUED SELECTIVITY SHOULD UPGRADE GROWING STOCK THROUGH TIME UNEVEN-AGED, WITHIN STAND -HIGH VSD -NO HSD an uneven-aged community 57

58 Compare even- and uneven-aged stands EVEN-AGED, WITHIN STAND -LOW VSD - NO HSD UNEVEN-AGED, WITHIN STAND -HIGH VSD - NOMINAL (MICRO) HSD At the stand level they differ Uneven-aged... Even-aged... 58

59 At the stand level they differ but what if applied across an ENTIRE FOREST 59

60 A FOREST UNDER EVEN-AGED MANAGEMENT by making conditions in adjacent stands distinctly different 36 stands 2 6 stands per age class Great differences between stands Looking to maximize HSD across the forest with even-aged systems... at the multi-stand or landscape level 60

61 Much edge high level of HSD After Patton 1992 A FOREST UNDER UNEVEN-AGED MANAGEMENT stands with 2 cut during EACH year under a 15-year cutting cycle Will actually provide little HSD across the forest... because conditions in adjacent stand differ little 61

62 NO difference between stands NOMINAL HSD CONTINUOUS VSD some variation in distribution of the largest trees... at the multi-stand or landscape level no edge little HSD After Patton

63 Uneven-aged Even-aged... they differ at the stand level, too 63

64 Consider a common conceptual model for wildlife From Patton 1992 But is this really practical at a landscape scale... 64

65 Look at a typical landscape in central New York... note the broken landscape pattern with ownership boundaries creating an unnatural landscape pattern 65

66 So how to effectively manage at the landscape scale... Perhaps it will become clear some day After Nissen