Is partial cutting a good way to manage black spruce forest ......Residual-tree growth responses to...

Is partial cutting a good way to

manage black spruce forest on

hydromorphic soils?

⊷ By Samuel Roy Proulx, ⊷ Yves Bergeron (UQAT), Sylvain Jutras (Université Laval) and Alain Leduc (UQAM)

International Boreal Forest Research Association, Laxenburg, Austria, September 2018

Why is this territory vulnerable to successional paludification? ⊷ The last glaciation⊷ Cold climat⊷ Low decomposition rate⊷ Time between fire events⊷ Traditionnal forest management

• Clear Cut• What about partial cutting?

References: Bergeron et al., 2006; Bergeron et Fenton, 2012; Fenton et al ., 2005; Lafleur et al., 2010; McRae et al. 2001

2Source image: Fenton et Bergeron 2011

Organic soil

Mineral soil

Water table

Clear Cut

3

• Regeneration

• Paludification

Partial cutting

?

?

? ? ?

4

• Interception

• Evapotranspiration

Organic soil

Mineral soil

Water table

Girdling

?

?

? ? ?

5

• Interception

• Evapotranspiration

Organic soil

Mineral soil

Water table

Objectives

Quantify the water table variations following partial

cutting and girdling treatments.

Study the influence of water table variations on black spruce growth and on

bryophyte communities.

6

7

• The main driving force of the water table one year after partial cutting is the interception of the tree cover.

• The reduction of evapotranspiration will not have a significant effect on the water table one year after the treatment.

• The girdling will isolate the effect of interception and remove the evapotranspiration on the water table.

• The water table variation and the removal of tree cover will have an effect on wood cell deposit of residual black spruce.

Hypothesis

Methodology⊷ Study area• Northwestern Quebec (Abitibi)• Black spruce-feathermoss domain• Clay Belt⊷ Study duration• Growing season (May-Sep)• 2 years ⊷ Silvicultural treatment 40%• Partial cutting 3x• Girdling 3x• Control 3x⊷ Before After Control Impact

8

20m

20m

Partial cutting

Girdling

Control

~200m x 200m

Block

Parcelle

Methodology

20m

20m

9

10

• Water table• Interception• Precipitation

• Dendrometers on 45 black spruce• Micro-coring on 45 black spruce

Hydrology

Dendrology

• Identification of bryophytes species• Sphagnum growth• Shift in bryophytes species

Ecology

Methodology

Hydrology

Changes in canopy openness

12

Results

13

Hydrology model result:

Rain events + Temperature + Block + Canopy + JDAY

POT HT HAN

0 - 365

List of variables:TemperatureJDAYRain eventsRain events with one day delay

List of factors: Canopy opennessYearTreatmentsPeriodBlock

14

Results

15

Results

Drought periods

Rain events

16

Drought periods:

Significant factors: Temperature + Block

Rain events:

Significant factors: Rain events + Temperature +Block

Results

POT HT HAN

POT HT HAN

POT HT HAN

17

Results : Drought periods

Results: Rain events

18

Discussion

Hypothesis: The main driving force on the water table one year after partial cutting is the interception of the tree cover.

Hypothesis: The reduction of evapotranspiration will not have a significant on the water table one yearafter the treatment.⊷We did not find any significant effect of

the treatments.

19

Discussion

• Hypothesis: The girdling will isolate the effect of interception on the water table.

⊶ The effect of interception is not significant on the water table.

Dendrology

20

21

Results

22

Discussion

Hypothesis: The water table variation and the removal of tree cover will have an effect on wood cell deposit of residual black spruce. ⊶ Black spruce radial growth may

change after a few years.⊶ This bioclimatic domain dynamic is slow.

Reference: Thorpe et al. 2007

23

Conclusion

⊷Hopefully, those results will helppromote partial cutting in black spruce forest on hydromorphic soils.⊷What’s next? • Follow the water table, black

spruce and sphagnum growth on the long term.

Thanks to the partners of the

project!

24

25

ReferencesBergeron, Y., D. Cyr, C. R. Drever, M. Flannigan, S. Gauthier, D. Kneeshaw, È. Lauzon, A. Leduc, H. L. Goff, and D.

Lesieur. 2006. Past, current, and future fire frequencies in Quebec's commercial forests: implications for thecumulative effects of harvesting and fire on age-class structure and natural disturbance-based management.Canadian journal of forest research 36:2737-2744.

Bergeron, Y., and N. J. Fenton. 2012. Boreal forests of eastern Canada revisited: old growth, nonfire disturbances,forest succession, and biodiversity. Botany 90:509-523.

Fenton, N., N. Lecomte, S. Légaré, and Y. Bergeron. 2005. Paludification in black spruce (Piceamariana) forests ofeastern Canada: Potential factors and management implications. Forest Ecology and Management 213:151-159.

Fenton, N. J., and Y. Bergeron. 2011. Dynamic old-growth forests? A case study of boreal black spruce forestbryophytes. Silva Fennica 45:983-994.

Jutras, S., A. P. Plamondon, H. Hökkä, and J. Bégin. 2006. Water table changes following precommercial thinning onpost-harvest drained wetlands. Forest Ecology and Management 235:252-259.

Lafleur, B., D. Paré, N. J. Fenton, and Y. Bergeron. 2010. Do harvest methods and soil type impact the regeneration andgrowth of black spruce stands in northwestern Quebec? Canadian journal of forest research 40:1843-1851.

McRae, D., L. Duchesne, B. Freedman, T. Lynham, and S. Woodley. 2001. Comparisons between wildfire and forestharvesting and their implications in forest management. Environmental reviews 9:223-260.

Thorpe, H., S. Thomas, and J. Caspersen. 2007. Residual-tree growth responses to partial stand harvest in the blackspruce (Picea mariana) boreal forest This article is one of a selection of papers published in the Special ForumIUFRO 1.05 Uneven-Aged Silvicultural Research Group Conference on Natural Disturbance-Based Silviculture:Managing for Complexity. Canadian journal of forest research 37:1563-1571.

0

200

400

600

800

1000

1200

1400

1600

1800

20/05/2017 25/05/2017 30/05/2017 04/06/2017 09/06/2017 14/06/2017 19/06/2017 24/06/2017 29/06/2017 04/07/2017

µm

POT2-10

POT2-14

POT2-18

POT2-29

POT2-31

POT2-30

POT2-2

Girdled trees

26

27

Results : Dendrology