logging in or signing up Soil nitrogen response to fire and thinning Urania Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Copy Does not support media & animations WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 210 Category: Education License: All Rights Reserved Like it (0) Dislike it (0) Added: February 05, 2008 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript “Near term response of surface soil nitrogen cycling and pools to forest clearing and burning”: “Near term response of surface soil nitrogen cycling and pools to forest clearing and burning” Heather E. Erickson Recent soils research from the Teakettle Experimental Forest, Sierra Nevada Mountains, CaliforniaSlide2: Background: Fire suppression over the last century has altered western forest ecosystems (increased tree densities, changed species compositions, and increased fuel loading) To return forest stands to “pre-suppression” conditions and to reduce the likelihood of catastrophic fires, fire and cutting are being re-introduced Slide3: Background: Nitrogen is a critical element in many forest ecosystems: likely influences post-disturbance successional dynamics and recovery of forest primary productivity and other key processes Given that forest restoration will occur over large areas, important to know how soil N (and C) pools and N transformations are affected by burning and cutting treatments Experiment at Teakettle:: Experiment at Teakettle: Designed to assess ecosystem effects of burning and thinning in mixed-conifer old growth forest (2200 m, west slope Sierra Nevada mountains) Large (4 ha) plots afforded opportunity to examine effects of restoration treatments on soil processesWhat others have found:: What others have found: Total N (and C) in forest soils either increase, decrease or remain the same after fire Inorganic N increases after fire but remains elevated for usually less than a year Wan et al. 2001, Ecol ApplTeakettle is a typical mixed-conifer forest: Teakettle is a typical mixed-conifer forest Conifers in discreet patches (CC) Shrub thickets (Ceanothus cordulatus) (CECO) Open areas mostly lacking vegetation (OC) CC OC CECOPre-treatment soils data (0-15 cm) show patches matter: Pre-treatment soils data (0-15 cm) show patches matter Under CECO, total N pools ~ 30% greater and net N mineralization more than double compared to other patch types Under OC, soils slightly more acidic, have a higher bulk density, and greater rock fraction percentage compared to other patch types Erickson et al., in revision, Forest ScienceMain research questions: Main research questions What are the effects of restoration treatments on N (and C) pools and N dynamics? Do differences among 3 patch types (CC, CECO, OC) carry over after restoration treatments?Slide9: 4 Treatments (codes): burning (B) burning plus light cutting (BC) burning plus heavy cutting (BS) and an un-restored control (U) 2 (4 ha) plots for each treatmentSlide10: 200 m 3 patch types 3 reps per type 6 sub-samples per patch Single composite sample per patch 9 patches x 8 plots = 72 patches * * * * * *ANOVA Table (Split plot): ANOVA Table (Split plot) Source of variation df Treatment 3 Plot (Treatment) 4 Patch 2 Patch x Treatment 6 Patch x Plot (Treatment) 8 Residual 48 Total 71Restoration treatments completed in 2001: Restoration treatments completed in 2001 Mineral horizon soils (0-15 cm) 1 and 2 years post-treatment Total N and C (dry combustion), inorganic N, pH (water), bulk densityTreatment effects (soil pools): Burning with cutting increased total N: Treatment effects (soil pools): Burning with cutting increased total N a a b b a a b b NTreatment effects (soil pools): Burning with cutting increased total N and C: Treatment effects (soil pools): Burning with cutting increased total N and C a a a a b b a a a b b b a a b b N CPatch effects (soil pools): Total N varied by patch pre- and post-treatment : Patch effects (soil pools): Total N varied by patch pre- and post-treatment a a b Total N - 2003Treatment effects (soil pH): Burning with cutting increased pH: Treatment effects (soil pH): Burning with cutting increased pH a a a a b b b bPatch effects (soil pH): OC patches were the most acidic pre- and post-treatment: Patch effects (soil pH): OC patches were the most acidic pre- and post-treatment a a a b b aTreatment effects (inorganic N): Burning with cutting increased NH4-N: Treatment effects (inorganic N): Burning with cutting increased NH4-N NH4-N T x P *Treatment effects (inorganic N): Burning with cutting increased NH4-N and NO3-N : Treatment effects (inorganic N): Burning with cutting increased NH4-N and NO3-N NH4-N NO3-N T x P * T x P *Interaction in 2003 suggests effect of treatment depends on patch : Interaction in 2003 suggests effect of treatment depends on patch a b a b b c c c c c cInteraction in 2003 suggests effect of treatment depends on patch : Interaction in 2003 suggests effect of treatment depends on patch a b a b b c c c c c c High nitrate in soils under CECO could be due to new N from fixationConclusions: Conclusions Burning and cutting treatments (BC, BS) significantly increase soil N pools, C pools, pH, and inorganic N relative to controls Burning alone (B) does little to affect soil properties Near-term effects are noted two years post-treatment Previous patch type also explains post-treatment variation in soil properties Acknowledgements: Acknowledgements Malcolm North USFS, PSW Range and Experiment Station International Institute of Tropical Forestry Model Institutions for Excellence (NSF) grant to Universidad Metropolitana Undergraduates from Universidad Metropolitana You do not have the permission to view this presentation. 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