Mitigating Seedling Establishment Measures for Riparian Restoration Success

Transcription

1 Mitigating Seedling Establishment Measures for Riparian Restoration Success Kent G. Apostol Central and Klickitat Conservation Districts Eastern Washington Riparian Symposium February 16, 2017

2 Acknowledgements Kaci Bartkowski Debbie Dumroese Anthony Davis Katy Kavanagh Owen Burney Dianne Haase Karma Bouzza Tom Landis Jeremy Pinto Layla Dunlap

3 Outline Challenges and impacts of riparian planting. Variability in site conditions. How do seedlings die and basis of seedling establishment. Planting techniques to improve seedling growth and survival.

4 Biggest challenge is to get these plants back on the landscape

5 Challenges of being a plant can t move much bottom of the food chain water/nutrients have to come to you Raven et al., 2010

6 What are the: Challenges of riparian planting: Defoliation of older age needle classes Reduced internode length Smaller denser needles Little or no growth the year following planting Branch death Mortality

7 Variability in site conditions Low moisture Shallow soil Low nutrients Climatic High temperatures Browse Shade Others? wildfire Haase, D 2014 Kavanagh, K 2014

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9 Movement of Water in Plants: From the Leaf to the Atmosphere Transpiration creates a water potential gradient that is more negative at the top of the tree. Tug-of war on hydraulic rope

10 When stomata are closed equilibrium exists -0.6MPa -0.6MPa -0.6MPa -0.6MPa -0.6MPa

11 When stomata are open, a gradient in water availability is established. -1.8MPa -1.5MPa -1.0MPa -0.9MPa -0.6MPa

12 Precipitation (in) Minimum temperature (F) Example of Climate data-priest River Experimental Forest, Idaho. USFS average daily data 1912 to Precipitation (in) Temperature (F) Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec 0 Why do seedlings sometimes lose the battle?

13 How do seedlings die? What happens during establishment if they experience severe drought? A dramatic reduction in growth Catastrophic failure of the tree s plumbing (hydraulic failure) system Carbon starvation

14 Objective: plant establishment GROW ROOTS! Perhaps the most important part of plant establishment in dry areas! Pinto et al., 2011

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16 Precipitation (in) Lbs C per acre per day Carbon acquisition is strongly related to 0.25 the amount of precipitation Precipitation (in) carbon gain or loss Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec -20 Precip from Priest River Experimental forest 1912 to 2006 USFS, Carbon (NPP) data generated using Biome BGC.

17 ANIMAL BROWSING

18 Limiting factors can be animals

19 Impacts of Ungulates Why is it that one species is preferred over the other? Typical browse preference for elk and deer: grass > forbs > shrubs > trees Conifer seedlings represent a crucial component of the diet during the WINTER. Hardwoods generally have greater browse during SUMMER (due to presence of foliage) Ramsey and Krueger 1986; Nelson and Leege 1982; Mansson et al. 2009

20 Impacts of Ungulates on Forest Regeneration DAMAGE: Terminal Shoot Lateral Shoot Entire Seedling (browsed or trampled) Pulled Seedling

21 Current efforts to Mitigate Animal Browse THERE IS NO BLANKET PRESCRIPTION Fencing Hunting Chemical Repellents (or dilute the palatability) Physical Barriers (tubing, bud caps) Frightening Devices (air canons) Fertilization Stimulate rapid growth, free to grow status above the browse line (control of competing vegetation)

22 Allocation of Resources Terpenoid Production Species Year Fertilizer Rate 0g 20g 40g 60g Western red-cedar Fall ab 1.7bc 2.0c 2.6d Douglas-fir Fall Western hemlock Fall mg g -1 [foliar dry weight]

23 Terpene production as browse deterrent? Fertilization promoted both plant growth and terpene production in western red-cedar NONE LOW MEDIUM HIGH Photos by Owen Burney

24 Post-planting drought stress: impacts of vegetation

25 1 st yr with veg comp Pinto et al Winter wheat

26 2 nd yr veg comp Pinto et al Year Year Year Year greenhouse greenhouse Note differences in needles and stem elongation from year to year.

27 Techniques to Mitigate the stresses Weed mats and browse tubes Shade cards Tree shelter

28 Red-flowering currant

29 Seedling stocktype can be used to overcome limiting factors N= no competition L=low competition H=high competition (Pinto 2009) (Thiffault 2004)

30 mid day leaf water potential (Mpa) Ponderosa pine super stock-hydraulics. leaf area (cm2) A y = Ln(x) R 2 = The larger the root, the less water stress Wt of root ball (gm) B y = x R 2 = The larger the stem, the more leaves stem caliper OB (cm)

31 Other amendments Hydrogel Biochar Year 1 (Application period ) Year 2 higher soil moisture and less nutrient leaching through the profile with biochar

32 Take-home messages Properly cultivated and selected seedlings can be one of the most effective ways to re-establish vegetation following a period of absence Understanding water in the plant and the environment container size, water delivery, timing, planting techniques, stress is key to riparian restoration success Survival should be measured 5 to 8 years post planting to know whether planted seedlings will establish Develop nursery protocols to help improve seedling survival rates Differences in field performance of plants produced across a range of container sizes New Project in our CDs: building a greenhouse to grow our own seedlings for riparian restoration projects