Relative impact. Time

Transcription

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2 Relative impact? Time

3 Relative impact MPB - Unique disturbance agent Larger & older trees selectively killed but remain standing (vs logging) needles can remain 3-5 yrs+ Understory & soil layers not directly affected (vs logging or fire) Return of nonvolatile nutrients to the soil & response of vegetation production are slower (vs stand-replacing fire)? Time 3

4 Broad research questions How much extra water is produced after different levels of red attack? (Pablo Piña) What are the early trajectories of post-attack vegetation and below-ground responses after different levels of red attack? (Anne McIntosh)

5 Approach & treatments Don t wait for MPB (issue of control ; B.C.) Simulate MPB attack variable density herbicide treatment Control (untreated) Simulated MPB attack (5% overstory kill) Simulated MPB attack (1% overstory kill) Clearcut - harvested to simulate salvage logging management 5

6 Stand water balance subplot (8 x 8 m; ha) ha) Stand water subplot (8 8 m; Vegetation subplot subplot (8 (8 x 6 6 m; m; ha) ha) Control Control (undisturbed) 5% 5% MPB MPB kill kill 1% MPB kill kill Salvage logged (harvested) plot - no trees left standing 2.2 ha x 1 ** 1 tree height (2m) exterior buffer between measurement plots & adjecent stand in in all plots Additional replicated plots for vegetation work = 12 x 1 m (1.2 ha ea) 4 treatments (below) x 2 replicates = 9.6 ha total 1.2 ha Control (undisturbed) 5% MPB kill 1% MPB kill Salvage logged (harvested) plot - no trees left standing x 2 Study duration 3 yr. yr. (1 (1 yr yr pre-treatment, 2 yr. post-treatment) 1 year pre-treatment measurements 2 years post-treatment measurements 12 stands Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oc, set up - instrumentation Pre-Treatment year Post-Treatment Year 1 Post-Treatment Year 2 Analys

7 Study area & design Pure pine ~ 12 yrs Medium site index m height Process studies Water balance - before-after: treatment-control Before After Treatment Control Understory vegetation - replicated (repeated measures)

8 ov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ja ut, set up - instrumentation Pre-Treatment year Post-Treatment Year 1 Post-Treatment Year 2 Analysis, write-up

9 Glyphosate late June 9 Harvest July ct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ayout, set up - instrumentation Pre-Treatment year Post-Treatment Year 1 Post-Treatment Year 2 Analysis, write

10 Bottom (Wind m/s) Bottom (VPD kpa) Bottom ( o C) Canopy regulated environmental factors 35 Air temperature Top ( o C) Understory light, air temperature, humidity, wind, etc. 1.8 Vapor pressure deficit Top (VPD kpa) 2.5 Wind Top (w ind m/s) Understory microclimate (compared to canopy) Air temperature (11 % lower, 1-2 o C) Moisture demand (14 % lower) Wind (51 % lower)

11 Harvested (wind m/s) Harvested (VPD kpa) Harvested ( o C) Canopy regulated environmental factors Air temperature Pre-treatment Post-treatment Understory light, air temperature, humidity, wind, etc Control ( o C) Before After 4 3 Vapor pressure deficit Treatment Control Control (VPD kpa) Wind Change in understory microclimate (@3 m ht) Air temperature - Tiny increase Moisture demand small/moderate increase Wind large increase 2 1 BATC powerful approach to document changes Control (wind m/s)

12 Post-attack hydrologic response Pablo Pina, PhD Student How much extra water is produced after different levels of red attack? 1. Changes in overstory rainfall interception 2. Changes individual tree & stand level transpiration - Can surviving trees compensate (use more water) 3. Changes in forest floor and soil moisture storage 4. Changes in water table level, groundwater

13 Vertical water balance framework Gross precipitation + Evaporative demand Overstory transpiration Canopy interception Forest floor interception Soil moisture storage

14 Rainfall interception Interception = Gross precipitation (Stemflow+Throughfall)-(Throughfall-Forest floor flow) Canopy interception Forest floor interception Overstory transpiration Canopy interception Forest floor interception Soil moisture storage

15 Canopy interception 6 m Stemflow N =3 Throughfall N= 4 Gross precipitation

16 Interception loss (mm) Canopy storage capacity (S) = 8.1 mm 12 1 Threshold Interception loss Predicted Storm (mm)

17 Forest floor interception.5 m Monitoring quadrats N =4 Forest floor quadrat.5 m

18 Forest Floor Weight (Kg) Forest Floor Recharge (mm) Post-treatment forest floor seasonal weight trends 12 1 Gross Precipitation (mm) 1 kill 5 kill Clearcut Control Harvested Julian Day

19 Water holding capacity (mm) Forest floor water holding capacity 12 Threshold 1 8 ~8.5 mm Storage opportunity (mm)

20 Storm frequency Storm frequency distribution based on rainfall intensity Threshold < >36 (mm)

21 Overstory transpiration Overstory transpiration Canopy interception N = 7 Forest floor interception Soil moisture storage

22 mm/day mm/day Pre-treatment Hourly transpiration Post-treatment 1% Kill 5% Kill Control

23 Soil moisture storage Spot measurements soil moisture (TDR) Overstory transpiration Canopy interception Time continuous soil moisture (WCR) Forest floor interception Soil moisture storage

24 Soil moisture storage (mm) Soil moisture at the Control plot 1 2 cm 4 cm 6 cm Spring melt recharge

25 Soil Volumetric Water Content Forest Floor Recharge (mm) Soil Moisture at 2 cm depth Forest Floor Recharge Control 1 Kill Clearcut 5 Kill Spring melt recharge Year 2 1

26 What will happen when the MPB kills the trees? mm 12 1 Precipitation Normals Site Data 425 mm 75% of annual gross precipitation) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

27 Conclusions: Overstory transpiration Canopy interception During the growing season: Canopy interception 49% of Precip Forest floor interception could be as high as canopy interception An average tree transpires 5.5 liters/day = >.7 liters/m 2 day Transpiration could be 41% of precipitation Understory evaporation? Forest floor interception Soil moisture storage Soil moisture recharge is mainly driven by spring snowmelt

28 Post-attack vegetation & below-ground responses Anne McIntosh, PhD Student What are the early trajectories of post-attack vegetation and below-ground responses after different levels of red attack?

29 Understory Overstory Belowground

30 Understory Overstory? MPB Belowground

31 MPB as a disturbance agent Larger & older trees selectively killed but remain standing (vs logging) Understory & soil layers not directly affected (vs logging or fire) Return of nonvolatile nutrients to the soil & response of vegetation production are slower (vs stand-replacing fire) OUTSIDE HISTORICAL RANGE: HOW WILL STANDS IN AB RESPOND?

32 Post-attack vegetation & below-ground response objectives What are the early trajectories of post-attack vegetation and below-ground responses after different levels of red attack? 1. Changes in overstory forest structure 2. Changes in understory plant community composition (shrubs, seedlings, plants (herbs, grasses, bryophytes) 3. Recruitment of downed woody debris (DWD) 4. Changes in below-ground processes (nutrient availability, microbial community, decomposition)

33 Objective 1: Overstory Characterize the overstory forest structure (.2 ha plots) Species Live status Dbh Height Crown vigor Cover (hemispherical photos) Measured before (28) & after (21) treatment 33

34 Basal area 6 LIVE DEAD 5 Basal area (m 2 /ha) %kill 5%kill Control Salvage Treatment * Post-treatment will be measured in 21

35 Trees per hectare 25 LIVE DEAD 2 Trees per Hectare %kill 5%kill Control Salvage Treatment * Post-treatment will be measured in 21 35

36 Mean DBH 25 2 All Live Dead Mean dbh (cm) %kill 5%kill Control Salvage Treatment * Post-treatment will be measured in 21 36

37 Objective 2: Understory Quantify differences in the understory plant community composition Seedlings/Saplings (pine) Advanced regeneration? MINIMAL Germination study (future regeneration potential) Plants (shrubs, forbs, graminoids, bryophytes, lichens) Richness Abundance (% cover) by species Basal area (large shrubs, e.g., alder)

38 Germination study (21) What is the regeneration potential of these stands after MPB? Quadrats on 5 substrates sowed with seed: LFH < 2.5 cm LFH > 2.5 cm Mineral soil Moss Dead wood (decay class 4-5) Monitor germination weekly

39 Understory richness Mean Richness by Stand %kill 5%kill Control Salvage Treatment 39

40 Understory cover ALDER FERN BRYOPHYTE GRASS SHRUB HERB 12 Cover (%) Kill 5Kill Control Salvage Treatment by Year

41 Understory cover: post-treatment (29) ALDER FERN BRYOPHYTE GRASS SHRUB HERB 12 Cover (%) a a a b 1%kill 5%kill Control Salvage Treatment

42 Objective 3: Downed woody debris Quantify DWD Transects: biomass estimates (Megagrams/ha) 42

43 DWD biomass Down Woody Debris (Megagrams/ha) %kill 5%kill Control Salvage Treatment

44 Objective 4: Below-Ground Quantify differences in below-ground attributes Decomposition (cellulose paper in mesh bags) ph Microbial biochemical activity & biomass Community-level physiological profiles (CLPP) Phospholipid fatty acid (PLFA) analysis Nutrient availability (PRS probes) Soil moisture (TDR) 44

45 Decomposition Mass loss (%) %kill 5%kill Control Salvage Treatment 45

46 ph ph 2 1 1%kill 5%kill Control Salvage Treatment 46

47 Total Nitrogen Total N (NO3 - and NH4 + ) Supply Rate (micrograms/1cm 2 /summer burial) %kill 5%kill Control Salvage Treatment 47

48 NO 3 - N (NO 3 - ) Supply Rate (micrograms/1cm 2 /summer burial) %kill 5%kill Control Salvage Treatment 48

49 NH 4 + N (NH 4 + ) Supply Rate (micrograms/1cm 2 /summer burial) %kill 5%kill Control Salvage Treatment 49

50 Understory Overstory MPB (short-term) Belowground

51 Recap & the future

52 Project timeline Fall 27 May 28: site selection, plot layout, instrumentation June 28 29: pre-treatment data collection June 29 July 29: treatment application June 29 21: 1 st post-treatment year data collection June : 2 nd post-treatment year data collection June 211 Mar 212: analysis and write-up Subsequent data collection?

53 What information will we have? Characterize water balance of these forests: Where the water is/goes How much water do they use? Characterize forest structure, vegetation, below-ground Relationships: canopy, understory vegetation, soils Potential for tree regeneration What happens when the trees die and stay standing?

54 Short-term responses of lodgepole pine forests to this unique disturbance Transpiration Interception Future forest development Soil water Soil nutrients Understory cover Species-specific responses Light? Below-ground communities Below-ground processes Understory community change Recover water balance?

55 Short-term responses of lodgepole pine forests to this unique disturbance Effects of gradient of disturbance: Water yield? Vegetation change? Recovery of water balance? Tree regeneration? Future forest development? LONGER TERM RESPONSES.?

56 Support for the work Foothills Research Institute FRIAA / AB SRD West Fraser Timber Co. Ltd. NSERC CONACYT Milo Mihajlovich Field Assistants Thank you for listening For further information: uldis.silins at ales.ualberta.ca ellen.macdonald at ales.ualberta.ca ppina at ualberta.ca amcintos at ualberta.ca