Cross Basin Comparison of the NYC Watershed

7/28/2019 Cross Basin Comparison of the NYC Watershed

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A Cross-Basin Comparison of the New York City Watershed

by

Ian B. BrentForest Science Intern

Under the Guidance ofDeborah LaytonForest Scientist

New York City Department of Environmental ProtectionWatershed Protection and Planning

Natural Resources Management

Ecological Research and AssessmentsForest Science Program465 Columbus Avenue, Suite 350

Valhalla, NY 10595


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Introduction

The New York City DEP is committed to ensuring sustainable eco-system health

and water quality for its citizens and consumers. In order to carry out this primedirective, it is important to constantly measure and study the environment inwhich the water dwells. A strong and diverse forest ecosystem will better filterand protect New York Citys water supply and ensure that it stays pure withoutthe aid of man-made filtration systems.

Baseline Continuous Forest Inventory (CFI) has been implemented on six basinsto date- Ashokan, Boyd Corners/West Branch, Rondout/Neversink, Schoharie,Pepacton and Cannonsville. This practice is necessary to ensure forest health,measure its regeneration from year to year, and to identify the proper times forsaw-timber removal. Using CFI, each watershed will be inventoried

approximately every ten years to eventually develop sound models of New YorkCity watershed forest dynamics which can predict forest growth, regenerationand mortality.

The data gathered from each watershed basin includes tree species, size class,timber quality, DBH (diameter at breast height), and site index (a measure ofheight growth potential as a function of stand age). These overstory observationsalso include: product grade, sawtimber height, pulpwood height, size class, andpercent canopy closure. Comments are recorded on presence of riparian zones,wetlands and interfering species (species that inhibit the regeneration of treeseedlings).

Understory data is also collected. This data includes a count of all saplings overa height of four and one half feet but less than four inches in DBH, percentgroundcover, foliage, rock, and leaf depth. Comments are also included, andmade on observed wildlife, invasive species, presence of insects and diseases,and percent slope and aspect are recorded.

Species richness is affected by the stress conditions to which trees are exposed.Physical features such as site conditions, extreme climate events, drought, andperiodic defoliation impact this important ecosystem. Competition, pathogens andover-grazing by White-tailed deer (Odocoileus virginianus) further stress thetrees. Over-grazing of saplings for many years depletes the younger age classes;when mature trees die, there is insufficient replacement, which leads to apopulation crash (Vatovec 2000).

Methods

Plot locations are specified by a grid system placed over a map of City-ownedforest lands. Plots are generally mile apart and each plot represents 160


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acres, with exception to the Ashokan Reservoir basin. Ashokan being the pilotproject of the CFI program, its plots are which are only representative of 100acres due to it being a pilot project before regular CFI plots were taken. Stayingon the grid and not arbitrarily establishing plots on the edge of City property isimportant to eliminate bias and provide accuracy in describing site conditions.

Plot centers are located by Global Positioning System; the center stake ishammered into the ground with plot number recorded on the stake with apermanent marker. The plot size is 1/5 of an acre, with a radius of 52.7 feet. Asonar-measuring device is positioned in the plot center; radii are measured out inall directions where pin flags are then positioned. At least seven pin flags arepositioned around the edge of the circular plot to facilitate determining whethertrees are located on or off the plot.

The tree closest due north and to the plot center would be tree number one.Trees are numbered out to the edge of the plot, and then back to plot center in a

clockwise direction. Only live trees that are four inches or over in diameter atDBHare tallied. These trees are measured to the nearest 1/10 of an inch and aremarked with a line at DBH using a paint marker and facing the plot center. Thetrees are numbered on the side facing the center plot with a bright blue aluminumdisk, which is nailed into the base of the tree. For trees on the plots edge,distance is measured by sonar to determine whether individual trees are inside oroutside the 52.7 radius, as necessary.

For each plot, measurements and observations are recorded in a hand heldcomputer. This field computer is equipped with a Windows operating system, andGPS. It is also loaded with NEDLite CE software to eliminate manual data entry

and reduce data entry errors.

Understory observations collected and recorded include saplings by species andsize class, including all trees and shrubs 4.5 feet or taller and with a diameterless than 4 inches. On denser and younger plots, the understory plot size isreduced in area to 1/10th of an acre (37.2 radius) to improve count accuracy. Allsaplings are tallied by one-inch diameter class.

Ground observations are also recorded. These include: percent groundvegetation coverage, leaf depth, slope shape, percent coverage of rock, ferns,interfering or invasive species, comments and presence of wildlife. Adjacency toriparian or wetland zones, and accessibility to stand and haul distance is alsorecorded.

Baseline data was summarized and initial analysis performed using the U.S.Forest Service NED-2 software as well as Microsoft Excel for basic statistics andcreation of charts and graphics. MiniTab statistical software was used to performcomparisons between basins.


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The baseline data for the Ashokan, Cannonsville, Neversink, Rondout,Westbranch, Boyds Corners, Pepacton and Schoharie Reservoir Basins issubject to change. Additional information will be provided following any impacts,extreme climate conditions, or urgent concerns.

Tables


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Table 1 (above.) Forest types of the NYC watershed system, with their respective total

acreages.

Forest

Type

Ashokan Boyds/West Cannonsville Neverond Pepacton Schoharie Totals

HemlockHardwood

200 160 2400 1440 1280 1120 6600

NorthernHardwoods

700 960 1920 800 1600 160 6140

AppalachianHardwood 300 1120 1120 160 640 0 3340

Oak

Northern

Hardwood

200 640 320 0 320 0 1480

pine-HW 300 0 160 0 0 960 1420Bottomland

Hardwood

0 320 640 160 160 0 1280

Allegheny

Hardwood

0 0 960 160 160 0 1280

maple 0 0 1120 0 0 0 1120PIST 600 0 160 0 0 160 920Oak 100 0 320 0 320 0 740

Hemlock 0 0 320 0 160 0 480Oak-

hickory

200 0 0 0 0 160 360

Other

Hardwood

0 0 0 160 160 0 320

Pine 100 0 0 0 160 0 260spruce-

northernHW

100 0 160 0 0 0 260

Pure PIRE 200 0 0 0 0 0 200Aspen-

Birch

0 0 0 0 160 0 160

beech-birch 0 0 160 0 0 0 160birch 0 0 160 0 0 0 160Pine-

hemlock0 0 160 0 0 0 160

aspen

northern

HW

0 0 0 160 0 0 160

Mesic

mixed pine-hardwoods

0 0 0 160 0 0 160

Pure ACRU 0 0 0 160 0 0 160Pure

QUPR2

100 0 0 0 0 100

Total 3,100 3,200 10,080 3360 5120 2,560 27, 420


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Basin DBH

(in.)

Basal

Area

Stems/Acre Slope

(%)

Wetland

(%)

Leaf

Litter

(%)

Ashokan 5.39 271.4 1152.6 10.23 2.26 4.60

Boyds/West 4.78 192.9 797.4 16.45 10.00 0.00

Cannonsville 6.25 207.3 1290.4 29.98 8.17 74.00Neverond 6.66 188.3 546.4 10.50 6.05 0.00

Pepacton 6.89 131.9 409.69 24.48 10.69 64.69

Schoharie 6.44 184.4 523.8 20.93 18.00 0.00

Table 2 (above.) Snapshot of averages across the NYC watershed system.

Figures and Charts

Section I: Totals and Snapshots

Cannonsville

Pepacton

Neverond

Boyds/West

Ashokan

Schoharie

Basin

9.3%

11.3%

11.7%

12.3%

18.7%

36.8%

Percentage of NYC Watershed by Basin

Figure 1-1: (Above) Percent Acreage of the NYC watershed broken down by Basin.


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PIST

Oak

Hemlock

Oak-hickory

Other Hardwood

Pine

spruce-northern HW

Pure PIRE

Hemlock Hardwood

Northern Hardwoods

Appalachian Hardwood

Oak Northern Hardwood

pine-HW

Bottomland HardwoodAllegheny Hardwood

OTHER

maple

Category

0.7%

0.9%0.9%

1.2%

1.3%1.8%

2.7%

3.4%

4.1%

4.4%

4.7%

4.7%

5.2%

5.4%

12.2%

22.4%

24.1%

NYC Watershed Diversity by Forest Type

Figure 1-2. Watershed-wide diversity analysis broken down into percent forest type. (Forthe purpose of clarity, forest types constituting less than 200 acres of the watershed were

condensed into category: OTHER. See table 1 for details.)

Boyds/WestAshokanCannonsvilleSchoharieNeverondPepacton

7

6

5

4

3

2

1

0

Basin

DBH

Average Overstory DBH (in) by Basin

Figure 1-3 (above). Comparison of average DBH in inches across NYC watershed basins.


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SchoharieCannonsvilleNeverondAshokanBoyds/WestPepacton

18

16

14

12

10

8

6

4

2

0

Basin

MerchDBH

Average Merchantable DBH (in)in the NYC Watershed by Basin

Figure 1-4, Comparison of Merchantable DBH in inches, across all six studied Basins.


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271.4

207.3

192.9 188.3 184.4

131.9

0

50

100

150

200

250

300

BasalArea(Sqft/Acre)

Asho

kan

Cann

onsville

BoydsC

orners/W

estbr

anch

Neversi

nk/Ron

dout

Scho

harie

Pepa

cton

Basin

Basal Area by Basin

Basal Area

Figure 1-5 (above). Comparison of average basal area (square feet/acre) across selected

NYC watershed basins.


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3005.010025

4716.2066

2823.04267

1270.763325

3150.060485

4671.841985

2650.66354

3451.9268

4169.631115

6701.5871

3774.5097

1996.432155

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

Biomass (Tons)

Basin

Biomass Totals (tons) for Lesser Basins

lg saw

med saw

sm saw

poles

lg saw 1270.763325 3451.9268 1996.432155

med saw 2823.04267 2650.66354 3774.5097

sm saw 4716.2066 4671.841985 6701.5871

poles 3005.010025 3150.060485 4169.631115

Neversink/Rondout Boyds Corners/Westbranch Ashokan

Figure 1-6- Snapshot of biomass in tons across the 3 lesser basins. (Lesser = Basins less

massive than 20,000 tons)


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355861.1882

394480.599

231840.3598

121917.0585

111069.7302

147513.7576

98249.55548

120777.3544

78916.04254

122559.0911

44142.58299

11654.92735

0

200000

400000

600000

800000

1000000

1200000

Biomass(tons)

Basin

Biomass Totals (tons) for Major Basins

lg saw

med saw

sm saw

poles

lg saw 121917.0585 120777.3544 11654.92735

med saw 231840.3598 98249.55548 44142.58299

sm saw 394480.599 147513.7576 122559.0911

poles 355861.1882 111069.7302 78916.04254

Cannonsville Pepacton Schoharie

Figure 1-7 Snapshot of biomass in tons across the 3 major basins. (major = Basins


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Average Age across Basins

78 77

7068

66

56

0

10

20

30

40

50

60

70

80

90

Asho

kan

BoydsC

orners

/Westbr

anch

Neversink

/Ron

dout

Pepa

cton

Cann

onsville

Scho

harie

Basin

Age

Averag

Figure 1-8 (above) - Snapshot of average ages (years) across studied basins.


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0

2

4

6

8

1 0

1 2

1 41 6

1 8

A

verag

e

W

etlan

d

(%

C

o

ver

)

B a s i n

A v e r a g e P e r c e n t W e t l a n d A c r o s s S e l e c t e d

B a s i n s

% W e t l a n d

% W e t l a n d 1 8 1 1 1 0 9 6 2

S c h o h a r i

eP e p a c t o n B o y d s / w

e s t

C a n n o n s v

i l l eN e v e r o n d A s h o k a n

Figure 1-9 (above) Snapshot of Average Wetland coverage by Basin.

Section II: Breakdown of Top Six Forest Types by Basin


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Cannonsville

Neverond

Pepacton

Schoharie

Ashokan

Boyds/West

Category160, 2.4%

200, 3.0%

1120, 17.0%

1280, 19.4%

1440, 21.8%

2400, 36.4%

Total Hemlock Hardwood Acreage by Basin

Figure 2-1 (above). Hemlock Hardwood forests broken down by respective presence inNYC watershed basins. (Acres represented next to percentage)

Cannonsville

Pepacton

Boyds/West

Neverond

Ashokan

Schoharie

Category

160, 2.6%700, 11.4%

800, 13.0%

960, 15.6%

1600, 26.1%

1920, 31.3%

Total Northern Hardwood Acreage by Basin

Figure 2-2 (above). Northern Hardwood forests broken down by respective presence in

NYC watershed basins (Acres represented next to percentage).


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Cannonsville

Boyds/West

Pepacton

Ashokan

Neverond

Category

160, 4.8%

300, 9.0%

640, 19.2%

1120, 33.5%

1120, 33.5%

Total Appalachian Hardwood Acreage by Basin

Figure 2-3(above). Appalachian Hardwood forests broken down by respective presencein NYC watershed basins. (Acres represented next to percentage, basins devoid of this

forest type were excluded for the purpose of clarity.)


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Cannonsville

Pepacton

Neverond

Category

160, 12.5%

160, 12.5%

960, 75.0%

Total Allegheny Hardwood Acreage by Basin

Figure 2-4 (above.). Allegheny Hardwood forests broken down by respective presence inNYC watershed basins. (Acres represented next to percentage, basins devoid of this



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Schoharie

Ashokan

Cannonsville

Category

160, 11.3%

300, 21.1%

960, 67.6%

Total Pine-Hardwood Acreage by Basin

Figure 2-5 (above). Pine-Hardwood forests broken down by respective presence in NYCwatershed basins. (Acres represented next to percentage, basins devoid of this forest type

were excluded for the purpose of clarity.)

Boyds/West

Pepacton

Cannonsville

Ashokan

Category

200, 13.5%

320, 21.6%

320, 21.6%

640, 43.2%

Oak-Northern Hardwood by Basin


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Figure 2-6 (above). Oak-Northern-Hardwood forests broken down by respective presence

in NYC watershed basins. (Acres represented next to percentage, basins devoid of this


Cannonsville

Boyds/West

Pepacton

Neverond

Category

160, 12.5%

160, 12.5%

320, 25.0%

640, 50.0%

Total Bottomland Hardwood Acreage by Basin

Figure 2-7 (above). Bottomland Hardwood forests broken down by respective presence in

NYC watershed basins. (Acres represented next to percentage, basins devoid of thisforest type were excluded for the purpose of clarity.)

Section III: Basin Statistics

i) Ashokan


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Pine

spruce-northern HW

Pure QUPR2

Northern Hardwoods

PISTAppalachian Hardwood

pine-HW

Hemlock Hardwood


Oak-hickory

Pure PIRE

Oak

Category

100, 3.2%

100, 3.2%

100, 3.2%

100, 3.2%

200, 6.5%

200, 6.5%

200, 6.5%

200, 6.5%

300, 9.7%300, 9.7%

600, 19.4%

700, 22.6%

Breakdown of Ashokan Basin by Forest Type

Figure 3-1 (Above): Ashokan watershed basin analyzed by Acreage of Forest Type(Acres of Forest Type are represented next to percentages, see table 1 for details).


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0

500

1000

1500

2000

2500

3000

3500

Biomass (Tons)

by Timber size class

Aboveground Biomass for Ashokan Reservoir Basin

lg saw

med saw

sm saw

poles

lg saw 605.836 566.526 563.722 0 260.348 0 0 0 0 0

med saw 744.652 1232.43 504.257 393.11 277.516 131.04 94.2196 141.354 0 97.7571

sm saw 1096.65 1293.42 465.868 726.557 293.924 505.683 537.8 432.486 513.421 159.621

poles 855.519 292.386 417.385 603.716 205.671 372.48 225.616 123.949 87.7681 272.47

ACRU QURU PIST ACSA3 FRAM2 QUPR2 TSCA PIRE QUAL BELE

Figure 3-2 (Above): Biomass of Ashokan watershed analyzed by tons and by Timber size

class. (Top 10 most massive species included, attached data table is in Tons).

ii) Pepacton


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Pine

Aspen-Birch

Northern Hardwoods

Hemlock Hardwood



Oak

Bottomland Hardwood

Allegheny Hardwood

Hemlock

Other Hardwood

Category160, 3.1%

160, 3.1%160, 3.1%

160, 3.1%

160, 3.1%

160, 3.1%

320, 6.3%

320, 6.3%

640, 12.5%

1280, 25.0%

1600, 31.3%

Breakdown of Pepacton Basin Acreage by Forest Type

Figure 3-3 (Above): Pepacton watershed basin analyzed by Acreage of Forest Type(Acres of Forest Type are represented next to percentages, see table 1 for details).

df

0

20000

40000

60000

80000

100000

120000

Biomass(Tons)

Species

Pepacton Biomass (Tons)

Lg. Saw

Med. Saw

Sm. Saw

Pole

Lg. Saw 54912.8 0 17967.1 3229.72 0 0 2608.83 0 1902.41 0 0 0 0 0

Med. Saw 28297 24141.7 12218 18366.4 0 1786.44 0 2800.7 1800.68 2855.31 1070.86 913.763 1743.57 852.351

Sm. Saw 26546.1 30834.1 21231.4 15186.6 4717.96 9241.52 5852.81 5169.59 4694.82 8249.12 2481.05 5142.04 2417.31 400.613

Pole 9118.92 21655.1 20890.4 10392.2 1932.79 10657.3 10408.2 6770.05 6005.88 1216.39 5047.48 1192.9 190.097 2754.96

QURU ACRU TSCA ACSA3 QUAL BELE FAGR FRAM2 PIST BEAL2 ACSA2 PRSE2 TIAM POTR5


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Figure 3-2 (Above): Biomass of Pepacton watershed analyzed by tons and by Timber size

class. (Top 14 most massive species included, attached data table is in Tons).

iii) Schoharie

Hemlock Hardwood

pine-HW

Northern Hardwoods

PIST

Oak-hickory

Category160, 6.3%

160, 6.3%

160, 6.3%

960, 37.5%

1120, 43.8%

Breakdown of Schoharie Basin by Forest Type

Figure 3-2 (Above): Schoharie watershed basin analyzed by Acreage of Forest

Type (Acres of Forest Type are represented next to percentages, see table 1 for

details).


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0

10000

20000

30000

40000

50000

60000

70000

80000

Biomass (Tons)

Species

Biomass (Tons) in Schoharie Basin

lg saw

med saw

sm saw

poles

lg saw 4095 1911 3170 0 0 0 0 0 0 0 0 0 0 0

med saw 18445 11614 4855 0 0 0 0 0 0 0 0 0 0 0

sm saw 35980 32702 15123 13981 578.8 1048 2674 0 0 0 0 0 0 0

poles 1769714435 9687 13197 1658 2383 752.1 1490 1190 1071 852.6 136.1 594.8 432.5

PIST TSCAACS

A3

ACR

U

THO

C2BEPA

PRS

E2JUVI

CAG

L8

BEAL

2

BEO

C2

CAC

A18

CAO

V2

ULR

U

Figure 3-2 (Above): Biomass of Schoharie watershed analyzed by tons and by Timber

size class. (Top 14 most massive species included, attached data table is in Tons).

iv) Cannonsville


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pine-HW

PIST

spruce-northern HW

beech-birch

birch

Pine-hemlock

Hemlock Hardwood

Northern Hardwoods


maple

Allegheny Hardwood

Bottomland Hardwood


Oak

Hemlock

Category

160, 1.6%

160, 1.6%160, 1.6%

160, 1.6%

160, 1.6%160, 1.6%

320, 3.2%320, 3.2%

320, 3.2%

640, 6.3%

960, 9.5%

1120, 11.1%

1120, 11.1%

1920, 19.0%

2400, 23.8%

Breakdown of Cannonsville Basin by Forest Type

Figure 3-5 (Above): Cannonsville watershed basin analyzed by acreage of Forest Type(Acres of Forest Type are represented next to percentages, see table 1 for details).


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0

50000

100000

150000

200000

250000

300000

Biomass (Tons)

Species

Aboveground Biomass in Canonsville Basin by Forest Type

lg saw

med saw

sm saw

poles

lg saw 19905 45682 37591 8936 0 3602 0 0 0 0 3602 0 0 0

med saw 46318 64593 43659 12310 1674 26064 13369 4491 2468 1674 26064 13369 4491 2468

sm saw 83736 81822 91712 37403 18639 17560 12716 19400 9499 18639 17560 12716 19400 9499

poles 1E+05 51127 48377 24767 33827 5243 12318 11252 12711 33827 5243 12318 11252 12711

ACRU TSCA ACSA3

FRAM2

FAGR QURU

BELE PRSE2

BEAL2

FAGR QURU

BELE PRSE2

BEAL2

Figure 3-2 (Above): Biomass of Cannonsville watershed analyzed by tons and by Timber

size class. (Top 14 most massive species included, attached data table is in Tons).

v) Neversink/Rondout


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Hemlock Hardwood

Northern Hardwoods


Bottomland Hardwood

Allegheny Hardwood

Other Hardwood

aspen northern HW

Mesic mixed pine-hardwoods

Pure ACRU

Category

160, 4.8%160, 4.8%

160, 4.8%

160, 4.8%

160, 4.8%

160, 4.8%

160, 4.8%

800, 23.8%

1440, 42.9%

Breakdown of Neversink/ Rondout basins by Forest Type

Figure 3-4 (Above): Neversink/Rondout watershed basins analyzed by acreage of ForestType (Acres of Forest Type are represented next to percentages, see table 1 for details).

0

500

1000

1500

2000

2500

3000

3500

Biomass(Tons)

Species

Biomass (tons) in the Neversink/Rondout Basins

lg saw

med saw

sm saw

poles

lg saw 424.7 377.3 327.6 65.92 75.27 0 0 0 0 0 0 0 0 0

med saw 828.5 658.6 445.1 282.3 121.2 159.7 140.8 40.01 76.69 31.63 38.57 0 0 0

sm saw 1068 942.9 806.9 456.1 242.4 337.8 244.2 211.4 132.2 113.7 95.94 44.89 0 19.79

poles 703.7 660.5 476.1 93.97 247.1 260.9 87.43 153.7 169.2 75.57 37.62 0 8.211 0

TSCAACR

U

ACS

A3

PRS

E2

FAG

RBELE

QUR

U

BEAL

2

FRA

M2

MAL

US

POG

R4JUNI

AME

LATIAM


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Figure 3-2 (Above): Biomass of the Neversink/Rondout watershed analyzed by tons and

by Timber size class. (Top 14 most massive species included, attached data table is in

Tons).

vi) Boyds Corners/Westbranch


Northern Hardwoods


Bottomland Hardwood

Hemlock Hardwood

Category

160, 5.0%

320, 10.0%

640, 20.0%

960, 30.0%

1120, 35.0%

Breakdown of Boyds Corners/ Westbranch basins by Forest Type

Figure 3-6 (Above): Boyds Corners/Westbranch watershed basins analyzed by acreage of

Forest Type (Acres of Forest Type are represented next to percentages, see table 1 for

details).


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0

500

1000

1500

2000

2500

3000

Biomass(tons)

Species

Biomass (Tons) in Boyds Corners/Westbranch

lg saw

med saw

sm saw

poles

lg saw 185.6 1765 621.2 130.4 335.4 0 0 118.2 296.1 0 0 0 0 0

med saw 308 584.6 283.7 156.2 335.3 270.3 210.3 182.5 106.6 0 91.15 0 121.9 0

sm saw 1282 311.9 580 669.8 383.8 481.4 101.1 228.5 0 138.6 152.7 96.56 50.27 144.7

poles 1063 128 404.5 489 33.92 305.8 160.5 0 0 123.7 27.87 134.4 47.22 52.28

ACR

U

QUR

U

ACS

A3BELE

FRA

M2

QUP

R2

FAG

RTSCA LITU

CAG

L8

QUA

L

BEAL

2

CAO

V2

QUV

E

Figure 3-6-2 (Above): Biomass of the Boyds Corners/Westbranch watershed analyzed by

tons and by Timber size class. (Top 14 most massive species included, attached data table

is in Tons).

Discussion


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Overall, the watershed looks relatively stable, but is headed in a direction towardparticular species dominance. Biomass indicates that to this effect, selectiveharvest may be beneficial in 5 to ten years for most basins, but overall watershedhealth looks consistent and promising. Assuming no invasive intrusions arepermitted, the watershed may continually edge closer towards being more

Hemlock-dominant. In 20 years time, it can be predicted that withoutintervention, the watershed will be very diversity-deficient.

The most dominant forest type in the watershed is Hemlock Hardwood. Thesemixed and complicated stands are good for drainage and filtration, however maypose risks to less tolerant forest types, such as red pines and pin/white oaks (onebeing specifically flood tolerant, and the other drought tolerant). This is becauseof several factors- one, hemlocks tend to create their own acidic environmentwhich may suit them (but are often intolerable to other species) and two, suddenmortality is rare among hardwoods, and unless thinning or branch diebackoccurs, sudden overgrowth can rapidly smother the forest floor underneath its

canopy.

Trailing right behind the dominant Hemlocks are Northern Hardwood stands,comprising almost a quarter (about 23%) of the entire NYC watersheds forests(Fig. 1-2). These forests tend to prefer moderately to well-drained soils, andconstant moisture. The near ubiquitousness of this forest type thoughout thewatershed indicates that current filtration methods are working well, and drainingis occurring properly, though many of these basins, as previously stated couldbenefit from a thinning or selective harvest. This ensures healthy regeneration ina forest type where mortality is uncommon, and overgrowth can happen rapidly.

Schoharie, the youngest basin, is an interesting example of the resilience anddiversity of the NYC watershed. It is the least biomassive, but has the mostwetlands per acre, by far, of any other basin in the watershed. This is probablydue to the recent development in the area, recent thinning and logging, and tothe use of off-site areas as agricultural fields. The Eastern White Pine (Pinusstrobus) stands that were planted in the areas around the Schoharie reservoirwere probably planted in much drier soils (preferred soils to white Pines), buthave adapted admirably to these new conditions- possibly because of the deeproute systems that allow for soil that has not yet been compacted to percolatewater more efficiently.

- PIST requires coarse and dry soils (sands, gravels and rocky outcrops)- Require frequent burns- Deep Root system

- Schoharie most relative wetland area

- Least biomassive


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- Second smallest basal area

-

Unfortunately the assumption that no invasive species will affect our projectionscan no longer faithfully be made for the watershed. A multitude of inboundthreats have been observed at the outskirts of the NYC watershed, and arepoised to make a notable splash on species demographics of the area. Speciessuch as Hemlock Woolly Adelgid, Emerald Ash Borer and Asian Longhorn beetlemust be watched very closely to ensure that massive die-offs do not occur-specifically because 58.7% of the watershed is composed of only three dominantforest types (Figure 1-2). This limits species variety and not only is detrimental toforest health and longevity, but will ensure maximum impact of invasive species

intrusion. A healthy forest with marked and continuous growth will be able tomore effectively combat inbound threats to the basin and should invasive threatsestablish themselves, there stands to be less risk of total species decimation ifthe relative dominance of species is spread out among species.

Calculating the biomass for Boyds Corners/Westbranch (figure 3.6.2) reveals anoverabundance of large saw Red Oak (Quercus rubrum). This indicates thebasin would benefit from a harvest in that area, as it is one of the most massivespecies in that basin, second only to Red Maple (Acer rubrum). This is furthersupported by Boyds Corners/Westbranch being second largest out of the sixbasins in terms of Merchantable DBH, but lagging behind all of them in average

DBH (Figures 1-3 and 1-4). Reduction of overstory density within the Red Oakswill aid in seed dispersal, and encourage growth for the lower size classes. Thiswill in turn, aid in diversity and the overall health of the Boyds Corners andWestbranch watershed forests, and the NYC watershed as a whole. Prevailingforestry theory also holds that a healthy and diverse ecosystem is superior inwater quality control and filtration, to that of a similarly dense but diverselydestitute one.

Hemlock Hardwood is far and away being the most dominant forest type, andaccounts for almost a quarter of the entire watershed. (Figure 1-2) The HemlockWoolly Adelgid must be watched carefully to see that it does not wreak havoc onsuch a large area of watershed land, and to a critical and dominant tree species.Hemlock Woolly Adelgid is an aphid-like creature that feeds on and destroyshemlocks of all types found on the Eastern seaboard.

Emerald Ash Borer, or EAB, is another menace to be watched. Notorious for itsdecimation of over 70 million Ash trees in the United States alone (Wren 2009),its recently noted presence in the Catskills area should be of particular concernwhen discussing NYC watershed health. Ash can be found in many hardwood


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forest types, particularly Northern Hardwoods, which is the second mostpopulous forest type in the entire watershed (figure 1-2).

Asian Long-horned Beetle, estimated to have been in New York since the 1980s,is considered a larger threat than the Emerald Ash Borer OR Hemlock Wooly

Adelgid due to its wide variety of tree preferences. Instead of specializing itsappetite to one or two main species, it has been known to eat maple,horsechestnut, elm, willow, birch, poplar, and ash trees. In the NYC watershed,the major tree types affected would include all types of Maple, Ash and Oak. Themost biomassive trees in the watershed are as follows- Red Maple ispredominant- if not the most predominant- in all basins across the board. Thesame can be said for Sugar Maple. Red Oak comes in third with EasternHemlock trailing fourth. Considering the wide prevalence of both Oak and Mapletrees, and the already potent danger of the ash-dwelling Emerald Ash Borer theeffects of this insects arrival into the ecosystem would felt across the entirewatershed.

References

http://mff.dsisd.net/Balance/TreeDiversity.htm

Wren, Maureen. Emerald Ash Borer Found in NY State Press Release.Wednesday, June 17, 2009 13/Oct/10

http://www.nycgovparks.org/sub_your_park/trees_greenstreets/beetle_alert/beetle_alert.h

tml
http://mff.dsisd.net/Balance/TreeDiversity.htmhttp://www.dec.ny.gov/press/55725.htmlhttp://www.dec.ny.gov/press/55725.htmlhttp://mff.dsisd.net/Balance/TreeDiversity.htm

Cross Basin Comparison of the NYC Watershed

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