Curtis Day

"PUSHBUTTON" VIABLE ECOSYSTEMS

Abstract:
Over the last two years the Ochoco National Forest in central Oregon has had a team developing a Viable Ecosystems Policy. The aim of the policy is to base all land management practices on the maintenance of a functioning and viable ecosystem across the landscape. Implementing the policy requires the use of GIS and classified LANDSAT imagery to give resource specialists indications of seral and structural stages that are out of balance with historical vegetation.

By studying records dating back to 1870 the team was able to estimate "ranges of historical variation" that occurred on the Forest. A simple menu system allows the GIS operator to select the watershed for analysis and update LANDSAT-derived vegetation mapping. The model then generates seral stages by combining LANDSAT- derived species data with field-mapped plant associations; combines these seral stages with a LANDSAT-derived size/structure layer; performs a neighborhood analysis to develop stands; and outputs a report and map showing stands that are outside historical ranges of variability.

In March of 1992, the Ochoco National Forest formed the Viable Ecosystem Quality Action Team, herein referred to as The Team. The Team was formed in response to employees' desire to make the maintenance of ecosystems the primary goal of all our management activities. The newly completed policy is currently under peer review and is being presented across the country to various groups. Two years of scientific work and policy development have been translated into a GIS application where the operator pushes four buttons to see where and how the policy can potentially be implemented on the ground.

Definitions
"Viable ecosystem" is the term to describe a living system of any community of organisms and that community's environment which:

1. provides conditions which sustain a full compliment of native species, including those which we have yet to identify;
2. is resilient to stress and adaptable to long-term climatic changes;
3. sustains its diversity, and productivity largely through natural processes;
4. sustains productive soils, clean water and air, and a rich biota;
5. maintains landscape patterns through natural processes, forming mosaics in the landscape;
6. provides conditions which encourage the recovery of populations of endangered, threatened, and sensitive species;
7. fluctuates widely over time and is dynamic with or without human intervention.

Problem Statement


The various ecosystems that currently comprise the Ochoco National
Forest are the result of forces that modified succession.  Fires or
lack of fires, timber harvest, grazing, other management activities,
and natural phenomena affected patterns of vegetation on these lands.
Current land management practices focus on forest outputs or
commodities, rather than on establishment and maintenance of ecosystems
and their processes.  Future management of this forest will reverse
these priorities. The objectives of this application are:

To recommend plant community conditions necessary to re-establish and maintain a 

viable ecosystem;

To provide information which will assist Forest managers in making decisions involving 

biodiversity and ecosystem management; and 

To provide a basis for describing cumulative effects of our management activities on 

communities of plant and animal species.


Assumptions


In preparing this management policy, the Team made these assumptions:


This application is intended to inform and assist managers with the decision-making 

process, not prescribe management activities.

This application provides descriptions of desired conditions to sustain viable 

ecosystems;

This application does not estimate commodity production or recommend any specified 

level of commodities. We assume instead that by managing for a viable ecosystem, a 

sustained flow of products is one possible outcome; 

As we have identified and described it in this application, "historic condition" assumes 

that the complement of native species was viable in the conditions that existed prior to 

European settlement.




METHODS



Determining Historical Range of Variation



To describe historic conditions information was gathered from conferences, workshops, 

stand exam data, scientific publications and journals dating back to 1870.  



Landscape Classification



The Ochoco National Forest is a diverse landscape of varied soils, elevation, and aspect. 

These features of the land influence climate and vegetation. Fire has also shaped 

vegetation patterns (Hall, 1989).  The Team developed a classification scheme for 

vegetation using two levels of classification.  The first level is the plant association group. 

Plant associations (Johnson, Clausnitzer, 1992) are used to describe site potential and are 

grouped based on similar successional responses to disturbance.  The second level is 

species composition and structural class.  The definitions and descriptions for each level 

follow. 



Plant Association Groups.  The Team classified over 80 plant associations into six plant 

association groups for the forested areas on the Ochoco National Forest.  Figure 1 depicts 

the plant association groups related to climatic conditions.

Figure 1.  Plant Association Groups described for the Ochoco National Forest.



Seral/Structural Stages.  Once the environmental gradient is classified by plant association 

group, the next step is to classify the existing plant communities that occur within a group.  

A successional classification is useful for this purpose.  A common conceptual model of 

secondary succession is shown in Figure 2.

Figure 2.  Matrix model of succession in a grand fir forest.



The two axis in the matrix model are size/structure and species composition.  Five 

size/structure stages are recognized (Table 1). 





TABLE 1. SIZE/STRUCTURE CLASS DEFINITIONS.  



Grass/Forb/Shrub			Trees may be present but are not the dominant vegetation

Seedling and Sapling 			<4.9" dbh

Pole     				5" - 8.9" dbh

Small      				9" - 20.9" dbh

Medium and Large			21" +  dbh



Note: Multi-story stands are stratified into the largest structural class that has 30 percent 

or more of the canopy cover. On drier sites, the site may be fully occupied with less than 

30 percent canopy cover. In this case the structure class would be based on the largest size 

class that makes up a majority of the vegetation cover. This table decribes the range of 

forest stucture conditions and is compatible with current inventory processes. These 

classes are based on the average diameter of the trees in the dominant tree canopy. (Pacific 

Meridian Resources 1992).  The species composition axis is divided into three stages: 

early, mid, and late seral.  In the early seral stage, shade intolerant species dominate.  

Mid-seral stages are dominated by mid-tolerant trees or by mixtures of shade tolerant and 

intolerant tree species.  Late seral stages are dominated by shade-tolerant tree species.  

Table 2 displays the matrix model of succession in a tabular form.

TABLE 2. Seral/Structure Matrix 



The seral/structural classification scheme serves as a model for describing historic 

conditions and management direction. Each seral/structural stage is not a uniform 

condition across the landscape, but varies by species composition, number of canopy 

layers, and density (stocking levels).  These stages are useful for assessing the successional 

progress of a stand and predicting the next plant community to occupy the site. 





APPLICATION



Background



The intent of the Viable Ecosystems Policy is to assist in producing a landscape vegetation 

condition that assures viability for all indigenous plants and animals.  It is intended to be 

implemented at the sub-watershed scale during the integrated resource analysis (IRA) 

process.  This policy links both the coarse and fine filtered aspects of ecosystem 

management.  Decisions for actual treatments are made at the fine filter level (individual 

stands and individual species treatments). Coarse filter application comes from describing 

and monitoring the abundance of seral/structural conditions at a forest-wide scale.  This 

provides for vegetation (habitat) diversity, through the allowance of localized over- and 

under-abundance.  For example, if a sub-watershed analysis showed an excess of the M5 

condition of the dry Grand Fir plant associations, the forest-wide view may show a lack of 

that condition.  That would help frame the purpose/need for planning in that sub-

watershed, i.e. treatment of the M5 condition would still probably not be appropriate.  

Similarly, if both the sub-watershed and forest-wide analysis showed an abundance of the 

M4 condition in dry Grand Fir, you would place a high priority on treatment of this 

condition to move it into a condition class where there are shortages.



The interdisciplinary team uses site-specific analysis of the vegetation mosaic and 

determines specific acres to be treated.  Consideration of special landscape features such 

as riparian zones, cliff faces, non-forest vegetation, etc. is given in relation to their 

juxtaposition with the forested environment.



Data Sources



PMR Data; Interpretation and Mapping.  The vegetation mapping done by Pacific 

Meridian Resources under contract to USFS Region 6 uses Landsat imagery and covers 

all USGS quadrangles that include National Forest land.  The mapping consists of multi-

spectral analysis of Landsat images to produce pixel maps of vegetation characteristics at 

a resolution of 25 meters.  



These pixel maps include information on size/structure, species composition, and canopy 

closure.  The PMR pixel data was incorporated into the Forest's geographic information 

system (GIS) through the GRID module of ArcInfo.  The two pixel layers which proved 

the most useful for this application were size/structure and species composition.  The 

size/structure pixel layer consists of 36 categories (see Appendix).  The Team grouped 

these 36 categories into the five size/structure categories described in the seral/structure 

matrix shown on page 5.  In GRID, these PMR categories were RECLASS'ed as values 1-5

as shown in the Appendix.  



The species composition pixel layer contains 97 categories for the Ochoco National 

Forest.  The Team grouped the 97 species categories into three representative seral stages 

for each of the six plant association groups as shown in Table 3.  These three groupings 

represent the Early (E), Mid (M), and Late (L) seral stages described in the seral/structure 

matrix on page 5.

  

Table 3.  Species Composition Data (reclassified by PMR from Landsat imagery) 

combined with plant association field data to derive seral stage.



Species Category			Plant Association Group

Value/Description	MA	DA	DF	PP	WJ	SA

8	/abgr////	L 	L	na	na	na	na

9	/abgr//mix//	L	L	na	na	na	na

10	/abgr//pipo//	M	M	na	na	na	na

					 ...

					etc.





Field Inventory.  Plant association mapping was completed by field personnel and 

manuscripted as a separate GIS layer.  These plant associations were stratified into the six 

plant association groups presented under METHODS.  In GRID the plant association 

polygons were POLYGRID'ed via a lookup table that assigned the plant association to 

one of the six groups as follows: Moist Grand Fir group (MA) = 100, Dry Grand Fir 

group (DA) = 200, Douglas Fir group (DF) = 300, etc.



Analysis



The analysis process consists of comparing the existing seral/structural conditions with the 

desired conditions for each plant association group.



In GRID, the LANDSAT-derived species layer is RECLASS'ed into six separate layers 

(one for each plant association group) with values of  10 (Early seral), 20 (Mid seral), and 

30 (Late seral) as shown in Table 3 above.  This layer and the LANDSAT-derived 

size/structure layer are then combined to create a new layer of Seral Stages by Plant 

Association Group.  In GRID these layers are simply added together to model Table 2 on 

page 5 (e.g. 11 = E1, Early seral/grass, forb, shrub; 12 = E2, Early seral/seedling,sapling; 

etc.).  When added to the POLYGRID'ed plant association layer, the resulting grid has the 

following values:



Value = xyz      	e.g. 134 = Moist Grand Fir/Late seral/Small trees



x  = 1-6					y = 1-3			z = 1-5

1 Moist Grand fir plant association group	1 Early seral		1 Grass/forb/shrub

2 Dry Grand fir plant association group		2 Mid seral		2 Seedling/sapling

3 Douglas fir plant association group		3 Late seral		3 Poles

4 Ponderosa pine plant association group				4 Small trees

5 Western juniper plant association group				5 Med/large trees



The next step is to generate a table comparing existing conditions and desired conditions 

based on the historical range of variation.  These are summarized by plant association and 

displayed in Table 4 on the next page.  This table is a specific example using the Moist 

Grand Fir Plant Associations in the Trout Creek Watershed as an illustration.  Percent 

refers to the percentage of land within the watershed.





Table 4.   Final Report from the Pushbutton Viable Ecosystems Application

				Trout Creek Watershed



                Existing Condition      Desired %

Matrix		Acres   Pvt.    %       Min.  Max.  % Difference  Acres 

Diff.

MOIST GF E1	682	0	9	5	12	0	0

MOIST GF E2	22	0	0	5	12	-5	-352

MOIST GF E3	913	23	12	5	15	0	0

MOIST GF E4	1,205	15	17	2	10	7	492

MOIST GF E5	176	0	2	2	5	0	0

MOIST GF M2	98	0	1	3	10	-2	-140

MOIST GF M3	1,293	10	18	5	20	0	0

MOIST GF M4	2,110	6	29	15	40	0	0

MOIST GF M5	193	0	2	10	20	-8	-563

MOIST GF L3	24	0	0	1	5	-1	-70

MOIST GF L4	103	0	1	4	8	-3	-211

MOIST GF L5	168	0	2	4	8	-2	-140

NON-FOREST	52	0	0	0	0	0	0



Maps are then constructed which display the spatial distribution of seral/structural stages 

across the landscape.   In this map the pixel data is filtered by a neighborhood analysis 

technique to consolidate larger areas of like seral/structural stages.  This map can be 

further processed to identify stands of specific acreages or within certain management 

allocations.  This process can also be used to generate maps for special purposes such as:


Present and potential Threatened and Endangered species habitat

Insect and disease risk ratings

Fire hazard ratings


Table 4 and the map are then used to provide the purpose and need for any management 

activity and the location of the seral/structural conditions potentially treated by that 

activity.  Prescriptions for any vegetative manipulation of a given seral/structural stage will 

be dictated by the surrounding seral/structural stages and special landscape features.



GRID notes of interest



Some of the challenges of writing this AML were meeting specific needs of the Team, 

such as removing stands of less than five acres, programming INFO to match existing vs. 

desired conditions, or generalizing the data for display purposes.  Dealing with missing 

plant association groups and/or private land in the DO loops was also a challenge.

CONCLUSIONS





Example Results



Table 5 displays some possible management strategies to bring the vegetation within the 

Trout Creek Watershed back within the historical range of variation.



Table 5  Management strategy for Trout Creek watershed based on current distribution of 

size/structural stages.



Seral/Structural Stage	Strategy                 



M3 and M4	Thin from below to promote growth to M5. Look for opportunities 

to promote L4 and L5 conditions-either with or without treatments.  

Emphasize creating or maintaining large blocks for old growth for 

old- growth habitat in the Moist ABGR plant association group.



E3 and E4	Thin or prescribe burn to promote E5 and prevent bark beetles.



E1	Encourage species variety to insure some stands moving into the M2 and L2 or L3 classes.



Key Points


This Application classifies vegetation on a landscape basis.

Management of vegetation is based on existing and potential conditions, not via set-asides.

The Viable Ecosytems policy applies Ecosystem Management principles to the ground.

It has become an integral part of Watershed Assessment.

It manages the landscape for a mosaic of vegetative types

Commodities are a product of the application, not driving it.

Viable Ecosystems has created a new common jargon on the Ochoco National Forest, where

fuels technicians, silviculturists, or timber planners can visualize the same stand 

structure and composition from the words M4 or L5.


ACKNOWLEDGEMENTS



The author wishes to thank the entire Viable Ecosytems Quality Action Team from whose 

guide much of this paper is plagerized.  Pacific Meridian Resources has provided the 

Ochoco National Forest with high quality spectral analysis and image processing that has 

greatly aided the development of this application. 







APPENDIX		Grouping of PMR Reclassified Landsat Imagery



Viable Ecosystem Class		Landsat Code and Description

1. Grass/Forb/Shrub   			4. Grass

					7. Shrub-vigorous

					8. Shrub-decadent

2. Seedling/Sapling  			10. Seed-Sap-Pole

					35. Sm/Seed

					36. Med/Seed-Sap

3. Pole 				11. Pole

					12. Pole/Sm

					20. Pole/MSLD

					21. Pole/MS+

					22. Pole/MS++

					37. Lg/Seed-Sap-Pole

					38. Gt/Seed-Sap-Pole

4. Small				13. Sm

					14. Sm/Md

					23. Sm/MSLD

					24. Sm/MS-

					25. Sm/MS+

					26. Sm/MS++

					39. Gt/Sm

5. Medium/Large			27. Med/MSDL

					28. Med/MS-

					29. Med/MS+

					31. Lg/MS-



Example definition of a Size/Structure category:

Lg/MS-     (Large/Multi-Sized minus)

This vegetation polygon did not meet single or two-sized canopy criteria or a multi-sized 

criteria.  There is at least 30% crown closure in Large.  There is a higher percentage of 

crown closure in trees smaller than large than in trees larger than Large (hence the "-").  

This is a common class in large old growth vegetation polygons.  This category typically 

has a "broken" canopy with structural diversity and trees in many of the size classes.