How fertilization and thinning may impact tree defense and mountain pine beetle overwintering

Devin Goodsman, Vic Lieffers, Nadir Erbilgin, and Simon Landhausser Centre for Enhanced Forest Management

Department of Renewable Resources University of Alberta

www.shim.bc.ca/atlases/fbc/ss3/Forest.html

Overview:

www.forrex.org

1. Fertilization and thinning and tree carbohydrate reserves

2. Mountain pine beetle overwinter survival in bolts from fertilized lodgepole pines

Starches: Immobile, reserves

Sugars: mobile

Carbohydrates in trees

Objectives: How does growth, stem size impact carbohydrate reserves?

Photosynthesis

Carbohydrate

Supply

Defense

Growth

Photosynthesis

Carbohydrate

Supply

Growth

Defense

Experimental Design

Fertilization Increased Growth Increment but decreased starch reserves

C F FT T

0

600

1200

1800

A

AB

B

A

Gro

wth

Incr

emen

t A

rea

(mm

²)

C F FT T

0

4

8

12

16A

AB

B

AB

Ro

ot

Star

ches

(%

Dry

wt)

Length of branchless stem impacts carbohydrate reserves in the roots

Ro

ot

star

ch (

% d

ry w

t)

Study 2: What if beetles kill and colonize fertilized lodgepole pines?

630ched.com

Description of experiment

Description of experiment

Description of experiment

More beetles survived in fertilized bolts

No impact of N on fungal growth (G. clavigera, L. longiclavatum, O. montium)

Fungi amplify nitrogen more effectively in fertilized bolts

Study 2: Implications

1. Fertilization increases phloem Nitrogen

2. Further amplified by fungal associates

3. increased survival and development rates in our beetles

Overall management implications

1. Fertilization reduces carbohydrate reserves in pine trees (For Ecol Manage (260): 1914-1920)

2. In fertilized trees, brood productivity will be higher (Upcoming issue of Environmental Entomology)

Thank you University of Alberta: Alberta SRD: Candace Serben Adrianne Rice Caroline Lecourtois Anina Hundsdoerfer Christine Dahl Barry White Eckehart Marenholtz Brooks Horne Evan Esch Darryl Gilday Kim Stang Dave Morgan Lucas Veldhoen Devin Letourneau Ryan Sherrit Jeffrey Mallete Pak Chow

FGYA