Appendix A ALB Host Tree Estimate Analysis.pdf

ALB Host Tree Estimate Analysis

Table 1.

• Table 1 estimates total host trees per acre and per land use category, as well as total trees (host and non-host) per acre and per land use category.

• Estimated total trees per acre is a product of the U.S. Forest Service. This nationally modeled dataset includes all stems with

DBH >= 1 inch.

• Because of inclusive stem count and the scale of the dataset (trees per acre scaled to 30m grid cells at the national level), the total number of trees per acre may be overcounted and less reliable then the estimated host trees per acre.

• Data elements related to host tree are a product of the merged survey data plus the contract tree survey scaled to the entire regulated area.

• Majority of Parcel in Land Use Category qualifies parcel by their majority land use category to show the proportions of parcels in different land uses.

Entire Regulated Area

Land Use

Majority of Parcel in Land Use Category

Total Parcel Area (acres)

Estimated Trees per Acre

Estimated Host Trees per Acre

Estimated Total Trees

Estimated Total Host Trees

Deciduous Forests 102 313 3,266 307 1,021,998 95,964

Mixed Forest 247 911 3,840 159 3,497,542 144,635

Evergreen Forest 1,843 6,249 3,370 96 21,061,469 599,231

Woody Wetlands 1,773 11,662 3,456 151 40,302,826 1,757,725

Emergent Herbaceous

Wetlands 481 6,812 405 96 2,759,385 653,233

Shrub/Scrub 1,778 3,318 1,921 151 6,374,131 500,074

Open Water 22 2,508 52 30 131,581 76,105

Table 2.

Surveyed Trees Estimated Trees

Land Use

Total Trees Surveyed Mean DBH DBH <= 6" DBH > 6" DBH >= 12” Estimated Total

Host Trees Estimated DBH

<= 6" Estimated DBH

> 6" Estimated DBH

>= 12"

Deciduous Forests 444 7.29 254 103 87 95,964 54,898 22,262 18,804

Mixed Forest 887 9.39 480 200 207 144,635 78,269 32,612 33,754

Evergreen Forest 6012 8.29 3,402 1,445 1,165 599,231 339,086 144,027 116,118

Woody Wetlands 26023 7.65 13,709 6,791 5,523 1,757,725 925,975 458,699 373,051

Emergent Herbaceous

Wetlands 280 9.27 122 91 67 653,233 284,623 212,301 156,309

Shrub/Scrub 1741 8.27 936 419 386 500,074 268,851 120,351 110,872

Open Water 99 7.03 50 23 26 76,105 38,437 17,681 19,987

• Table 2 uses the survey efforts of the ALB program to estimate DBH across the regulated area.

• Surveyed tree metrics are modeled from merged surveys data plus the contract tree survey. The point survey data is then parsed by land cover type and binned by DHB as a proportion of the whole.

• Once binned, the surveyed data are scaled to the estimate total host trees across the entire regulated area.

Table 3.

All Contract Trees

Land Use

Majority of Parcel in Land Use Category

Total Parcel Area (acres)

Total Contract Trees

Contract Trees per Acre

Mean DBH – Contract Trees

Estimated Total Host Trees (For Regulated Area)

Deciduous Forests 1 18.97 177 20.31 8.89 5,971

Mixed Forest 0 53.6 119 1.98 6.09 761

Evergreen Forest 18 286.88 1309 8.46 7.08 55,009

Woody Wetlands 59 860.81 16,847 13.68 7.71 225,108

Emergent Herbaceous

Wetlands 0 22.87 102 14.19 7.87 80,582

Shrub/Scrub 14 78.37 523 9.72 7.51 32,381

Open Water 1 32.65 42 4.64 10.24 1,357

• Data on contract tree totals, per acre counts, and DHB come from the contract tree survey data. The data is then scaled to the entire regulated area to estimate total host trees.

• The number of parcels containing contract tree surveys represent about 1.5% of the total parcels in the regulated area.

• Estimated total host trees per land use type or per acre may undercount the estimated total host trees compared to the combined dataset in table 2.