REGENERATION UNDER PARTIAL REGENERATION UNDER PARTIAL CUTTING FOR PROGNOSISCUTTING FOR PROGNOSISBCBC, ,

MSdk Subzone, MSdk Subzone, CRANBROOK FOREST DISTRICT CRANBROOK FOREST DISTRICT

Badre Tameme Hassani, M.Sc.,

Valerie LeMay, PhD., RPF, Peter Marshall,

PhD., RPF and Abdel-Azim Zumrawi, PhD., RPF

Presented at the Cranbrook District Office

November 6, 2002

Background• Understanding stand dynamics is necessary to achieve

management objectives• MoF has adopted PrognosisBC to predict the dynamics of

complex stands in the southern interior of BC• PrognosisBC is an adaptation of the US Forest Vegetation

Simulator (FVS); it forecasts future stand conditions based on the expected growth and mortality of individual trees

• It can be used to simulate a wide variety of stand management activities, including any form of harvesting

• PrognosisBC has been calibrated by the MoF, in conjuntion with the Faculty of Forestry at UBC, for use in southeastern BC since 1997

• It has been calibrated for use in several BEC subzones/variants in the Kamloops, Nelson, and Cariboo Forest Regions

• Calibration of large tree (height and diameter), live crown ratio, and mortality was done using PSP data

• Insufficient data limited the capability of the model to predict small tree height growth, regeneration, and to make long-term projections following harvesting

• Currently, the regeneration portion of PrognosisBC has been disabled; users must supply their own data

• Regression approaches did not lead to good predictions of regeneration

• Predicting the regeneration of complex stands in the ICH using imputation approaches proved to work better than regression

Objective

• Predict regeneration under partial cutting using the tabular imputation approach for complex stands in the MSdk subzone

Outline

• Location of the study area

• Methods

• Results

• Conclusions

• Current and future projects

Location of Study Area in BC

• Continental climate

• Middle elev. (1100-1650 m)

• Bounded by IDF (lower elev.) and ESSF (higher)

• Supports 11 trees species

Nelson Forest Region

Complex Stands in the MSdk zone

• Mixed species

• Uneven-aged

• Multi-cohort

• Subalpine fir and hybrid spruce are climax species

• Extensive presence of lodgepole pine and Douglas-fir

Potential PolygonsGroup (yrs)

CCRes CC Patch Seed-tree

Shelter-wood

Selection Missing*

1 (1-5) 38 5 6 5 3 0 2

2 (6-10) 51 81 4 81 10 21 0

3 (11-15) 1 37 0 33 0 11 1

4 (16-20) 5 13 0 59 0 11 2

5 (21-25) 3 42 0 48 0 10 0

* missing information on the silvicultural system

Plot Layout• Nested plots

• Systematically located in

selected stands

• Stands selected to cover the range of: overstory density age since disturbance site preparation slope percent aspect elevation

• 122 plots from 52 polygons

STP(3.99m)

LTP(=11.28 m)

Regen. P(2.07m) Satel. P

(2.07m)

Species Groups

Species Group Species

Shade tolerant Cedar, subalpine fir, spruce

Shade semi-tolerant Douglas-fir

Shade intolerant Larch, lodgepole pine

Hardwood Aspen, cottonwood, Douglas Maple, willow

Tabular Imputation Methods

Stand Conditions

• Basal Area class: Dense: > 5m2/ha; Open: =< 5m2/ha

• Site Series class: Dry: 02, 03, and 04 Wet: 01, 05

• Time-Since-Disturbance Group (years): Group 1: 1-8 2: 8-16 3: 16-25

Tabular Imputation Approach

For each stand condition combination: • Average number of seedlings per ha by:

height class (1: 15-49.9 cm for shade tolerant species and 30-49.9 cm for shade intolerant species, 2: 50-99.9 cm,

3: 100-129.9 cm, and 4: >130 cm) and for the 4 species groups (16 regeneration variables)

Precision of the tabular imputation modelsStandard error of the mean for each cell of in the tables

Results

Sampling and Regeneration Composition• 12 undisturbed, 13 clear-cut plots from 122 plots

• 69% of the plots were site series 04

• Overstory dominated by intolerant species (819 stems/ha)

Yrs since Disturbance

Yr # plots

0 12

5 6

5-10 41

10-15 15

15-20 22

>20 26

Site Series

SS # plot

02 2

03 9

04 84

01 23

05 4

Residual BA (m2/ha)

Meth # plot

0 8

1-5 40

5-10 26

10-15 14

15-20 9

20-25 5

25-30 5

30-35 4

35-40 2

>40 9

Silv. System

Method # plot

CC 13

CC/Res 15

Light shelter 2

Seedtree 42

Selection 23

Shelter/Selec 3

Shelter/ST 1

Shelter 11

Undisturbed 12

Elevation- 100m

Elev. # plot

<=900 0

9-10 6

10-11 8

11-12 30

12-13 25

13-14 20

14-15 26

15-16 7

Site Prep.

Method # plot

None 81

Burn 41

Aspect

Aspect # plot

E 19

F 15

N 7

NE 15

NW 16

S 6

SE 17

SW 6

W 21

Slope Position

Position # plot

Crest 1

Lower 10

Ridge 1

Middle 76

Plateau 18

Terrace 8

Flat 4

Upper 4

Slope Percent

Slope # plot

0-10 39

10-20 38

20-30 21

30-40 9

40-50 6

50-60 6

>60 3

Diameter Distribution for all residual species combined

0

100

200

300

400

500

600

700

2.5 7.5 12.5 17.5 22.5 27.5 32.5 37.5 42.5 47.5 52.5 57.5 62.5

5-diameter class midpoint

Av

era

ge

Ste

ms

/ha

Regeneration Composition

• Average regeneration (over 122 plots)= 6023 seedlings/ha

• Averages of 2168, 1522, 1285, and 1048 seedlings/ha for shade intolerant, hardwood, semi-tolerant, and tolerant species respectively

• 29 plots had no regeneration (zero)

Regeneration by Site Preparation Treatment

9242

4394

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Ave

rage

reg

ener

atio

n/ha

Burning None

Regeneration by Time-Since-Disturbance Groups

0

200

400

600

800

1000

1200

Avera

ge reg

enerat

ion/ha

Group 1 Group 2 Group 3

Time-since-disturbance group

Tolerant Semi-tolerant Hardwood Intolerant

1230

2576

2217

0

500

1000

1500

2000

2500

3000

Aver

age r

egen

erat

ion/h

a

Time-since-disturbance group

Group1 Group2 Group3

Tabular Imputation Models

12 tables were produced for the disturbed sites; 1 table for undisturbed sites

Dense, Dry, first 5 years since disturbance (n=7)

Species Height (cm) All heights

15-49.9 50-99.9 100-129.2 >130

Tolerant 0 0 0 0 0

Semi-tolerant 531 0 0 0 531

Intolerant 849 1168 0 106 2123

Hardwood 212 531 955 955 2653

All species 1592 1699 955 1061 53075307

Undisturbed Sites (n=12)

Species Height (cm) All heights

15-49.9 50-99.9 100-129.2 >130

Tolerant 743 62 0 0 805

Semi-tolerant 743 248 124 557 1672

Intolerant 0 0 0 124 124

Hardwood 0 0 0 0 0

All species 1486 310 124 681 26012601

SEM- disturbed sites: dense, dry, 5 yrs (n=7)

Species Height (cm) All heights

15-49.9 50-99.9 100-129.2 >130

Tolerant 0 0 0 0 0

Semi-tolerant 352 0 0 0 352

Intolerant 498 943 0 106 1636

Hardwood 137 420 738 955 1699

All species 524 927 738 943 20792079

SEM- undisturbed sites (n=12)

Species Height (cm) All heights

15-49.9 50-99.9 100-129.2 >130

Tolerant 419 62 0 0 461

Semi-tolerant 419 190 83 557 787

Intolerant 0 0 0 124 124

Hardwood 0 0 0 0 0

All species 593 193 83 681 930930

• Predictions based on three or less plots resulted in very high SEM (reaching 100 % of the mean in most cases)

• Predictions based on more than 10 plots had lower SEM

• Lowest SEM values were observed within tables based on more than 20 plots

Conclusions• Species composition of the overstory was dominated

by intolerant species followed by semi-tolerant species

• Treated sites had more regeneration than undisturbed sites

• Regeneration present on the disturbed sites were predominately comprised of seral species (intolerant and hardwood species)

• Regeneration was most abundant between 8 and 16 years after disturbance

• Shade tolerant and semi-tolerant species dominated undisturbed sites

• The tabular imputation approach made good use of the available data

• Tabular imputation models had a simple structure and provided detailed average post-harvest regeneration for different conditions

• Performance of this technique depends implicitly on the data used for the analysis

• These models are flexible and can be easily updated as more data become available

Acknowledgments

• This research was funded by Forestry Innovative Investment. In-kind support was provided by the BC Ministry of Forests, Research and Forest Practices Branches, UBC Faculty of Forestry, Tembec Industries, Riverside Forest Products, and Slocan Forest Products

Contact and Web Site

For more information, you can contact:• MoF Research Branch: Dr. Abdel-Azim Zumrawi

• UBC: Dr. Valerie LeMay and Dr. Peter Marshall

Web Site (for contact information and reports):• www.forestry.ubc.ca/Prognosis

• The final report will be available on the web by the end of November 2002

Work on progress:• Calibration of the PrognosisBC small tree height increment

model and development of regeneration imputation models for IDFdm2 in the vicinity of Invermere

Planned work:• Workshop at UBC to discuss future regeneration modelling

approaches (link of regeneration imputation techniques to PrognosisBC)

• Make the results accessible for users through the web• Consolidate the data collected over the past 5 years in

different zones into a single database (corporate database) for use and preservation

Current and Future Projects

Question for the Audience

• What other purposes could the data be used for?