Fire Ecology 2018 Annual Report Summary, Monitoring & Inventory

By Jennifer L. Barnes and Jennifer L. Hrobak

Figure 1. Lichens 14 years after a fire.

NPS photo

Summary

The National Park Service (NPS) Alaska region fire ecology program provides science-based information to guide fire and land management planning, decisions and practices in order to maintain and understand fire-adapted ecosystems in Alaska.

During the 2018 field season, the Alaska NPS fire ecology program conducted monitoring in Yukon-Charley Rivers NPr (Figure 1), continued to collect seasonal fuel moisture samples, and assisted with fire research projects. The regional fire ecologists were involved with preparing monitoring protocols, research reports, instructing classes, and participating on several agency and interagency committees. This annual report provides a brief summary about the NPS Alaska 2018 fire season, fire ecology monitoring results, fire research projects, and fire ecology program activities and outreach.

Monitoring and Inventory

Yukon-Charley Rivers – 14 years after the Woodchopper Creek fire
During this past summer (2018), Alaska Region fire ecologists re-measured permanent fire effects plots that were established before and after the 2004 Woodchopper Creek fire in Yukon-Charley Rivers NPr. These sites were established to document the effects of fire on vegetation and soils at 4 black spruce sites and 2 paper birch sites. The objectives of the study were to:

• Document vascular and non-vascular plant cover changes
• Monitor tree seedling establishment
• Document changes in tree densities by diameter size class
• Doocument changes in active layer depths and soil temperatures

The plots sampled were of two general vegetation types prior to the fire mesic black spruce (Figure 2) and paper birch forests (Figure 3 and Figure 4). The general changes in vegetation cover by dominant life form are shown in the graph in Figure 5. Fourteen years after the fire the understory shrubs and dwarf shrubs have recovered to pre-fire cover levels in the black spruce stands. The dominant shrub cover was Labrador tea (Ledum palustre) (42% cover) and shrub birch (Betula nana) (12% cover) and dominant dwarf shrub was bog cranberry (Vaccinium vitis-idaea) (31% cover). Sedge cover increased to greater than pre-fire cover, primarily tussock cotton-grass (Eriophorum vaginatum) (17% cover).

The paper birch sites had two different impacts. The high severity site (Figure 3) had hydrologic changes and a pond formed in the middle of the site. The moderate severity site had young sapling paper birch (Betula neoalaskana) dominating the site with bluejoint grass (Calamagrostis canadensis) (42% cover) understory (Figure 4).

Figure 2.  This black spruce forest was burned in 2004 by the Woodchopper Creek fire in Yukon-Charley Rivers NPr.  A few monitoring sites were established in front of the fire. Photos from the monitoring site are shown from left to right; pre-fire (2004), 1 year post fire (2005) and 14 years post fire (2018).

NPS photos

Figure 3. This paper birch forest was burned in 2004 by the Woodchopper Creek fire in Yukon-Charley Rivers NPr.  The site was established immediately after the fire in 2004.  Photos from monitoring site are shown from left to right; 1 month post fire (2004), 4 years post fire (2008), and 14 years post fire (2018).

NPS photos

Figure 4.  This paper birch forest was burned in 2004 by the Woodchopper Creek fire in Yukon-Charley Rivers NPr.  The site was established immediately after the fire in 2004.  Photos from monitoring site are shown from left to right; 1 month post fire (2004), 1 year post fire (2005), and 14 years post fire (2018).

NPS photos

Firgure 5. Point intercept vegetation cover data summarized for average cover by life form from the 2004 Woodchopper Creek fire monitoring plots in Yukon-Charley Rivers NPr.

NPS photos

Tree seedlings are important for the future forest that will occur after a fire. The average density of tree seedlings was quite variable (Table 1) among the plots and across the time since fire. The black spruce sites continued to have black spruce seedling establishment over the 14 years. Birch seedlings were prevalent the first year after fire, but seemed to die-off within the first year. The birch stands were dominated by birch seedlings. By 14 years post fire most of the seedling paper birch were tall enough that they were counted as trees rather than seedlings.

Table 1. Average seedling densities (trees less than 1.37 m tall) per meters squared by forest type and time since fire.

Forest Type and Time Since Fire	Number of Plots	White Spruce seedlings/m2 (80% Confidence Interval)	Black Spruce seedlings/m2 (80% Confidence Interval)	Paper Birch seedlings/m2 (80% Confidence Interval)
Black Spruce Plots Pre- Burn	2	0	0.67 (-1.38-2.72)	0
Black Spruce Plots Post Burn 1 Year	4	0	1.08 (0.36-1.80)	6.25 (2.64 - 9.86)
Black Spruce Plots Post Burn 4 Years	4	0	1.5 (1.34 - 1.65)	0.42 (0.16 - 0.68)
Black Spruce Plots Post Burn 14 Years	4	1.62 (-0.86 - 4.11)	2.58 (0.03 - 5.14)	0.54 (-0.04 - 1.12)
Paper Birch Plots Post Pre-Burn	1	0.17 (-0.35 - 0.68)	0	1.0 (-2.08 - 4.08)
Paper Birch Plots Post Burn 1 Year	2	0	0	98.7 (-49.06 - 246.39)
Paper Birch Plots Post Burn 4 Years	2	0	0	68.2 (-55.45 - 191.79)
Paper Birch Plots Post Burn 14 Years	2	0	0	3.7 (-1.98 - 9.31)