MRC logo
photo





Employee News




Issues and Policies

Mendocino Redwood Company Structure Classes

Forest structural conditions have strong associations with wildlife use. Mendocino Redwood Company's landscape planning tools include a component that classifies forest vegetation into groupings or classes of forest structure. Forest structure classes are based on:
  • Species dominance
  • Size dominance
  • Density of the forest
  Mendocino Redwood Company developed this system for determining structure classes in order to understand both the current condition of the forest and changes to forest structure resulting from forest growth and harvesting activities. The system was developed as an alternative to the California WHR (Wildlife Habitats Relationship) model because the WHR system was developed for even-aged management, where trees in a forest stand are very close to the same size and age. MRC manages its forest with uneven age harvesting. This means that there are trees from more than one age and size group in forested stands at all times. WHR determines the size of the forest stand utilizing an average. Averaging works well for forested stands where the distribution of tree sizes within a stand is minimal. It does not describe the condition of a forest with a wide distribution of sizes, as in uneven age management.

 

MRC has developed 24 different structure classes for its forested vegetation. The rules for determining a structure class can be seen on the Structure Class Determination page (Structure Classification Rules.htm).

 

 

Tree lists are generated for every stand from information collected during sampling activities in the field. These tree lists are used to determine structure classes. The landscape planning tools project the tree lists through anticipated harvests and growth to determine how forest structure is likely to change over time.

 

It is a goal of MRC to restore the forest composition to larger, denser, conifer stands.  MRC expects to see a trend toward larger, denser, conifer stands as each decade of MRC management passes.

 

Structure_Class

Vegetation

Dominant Diameter

Canopy Closure

Chart Symbol

1

Mixed Hardwoods

<8"

20 - 40%

H_4_

2

Mixed Hardwoods

>16"

20 - 40%

H_16_L

3

Mixed Hardwoods

<16"

40 - 60%

H_8_L

4

Mixed Hardwoods

>16"

40 - 60%

H_16_M

5

Mixed Hardwoods

<16"

>60%

H_8_D

6

Mixed Hardwoods

>16"

>60%

H_16_D

7

Mixed Conifers and Hardwoods

<16"

20 - 40%

M_4_L

8

Mixed Conifers and Hardwoods

16 - 24"

20 - 40%

M_16_L

9

Mixed Conifers and Hardwoods

<16"

40 - 60%

M_8_L

10

Mixed Conifers and Hardwoods

>16"

40 - 60%

M_16_M

11

Mixed Conifers and Hardwoods

<8"

>60%

M_4_D

12

Mixed Conifers and Hardwoods

16 - 24"

>60%

M_16_D

13

Conifer

<16"

20 - 40%

C_4_

14

Conifer

16 - 24"

<20%

C_16_O

15

Conifer

24 - 32"

20 - 40%

C_24_L

16

Conifer

>32"

20 - 40%

C_32_L

17

Conifer

<16"

40 - 60%

C_8_M

18

Conifer

16 - 24"

40 - 60%

C_16_M

19

Conifer

24 - 32"

40 - 60%

C_24_M

20

Conifer

>32"

40 - 60%

C_32_M

21

Conifer

<16"

>60%

C_8_D

22

Conifer

16 - 24"

>60%

C_16_D

23

Conifer

24 - 32"

>60%

C_24_D

24

Conifer

>32"

>60%

C_32_D



Back to Forum

 • back to top •


Home | About MRC | Forest Management | Issues & Policies | Employment | Forum | About Redwoods | Contact | Site Map
©2008 Mendocino Redwood Company          Privacy Policy
MRC® and the Mendocino® Redwood Company logo are federally registered trademarks of Mendocino Redwood Company, LLC, Ukiah, California.