| [Editor's Note: The following plan was presented at the Eco-Roundtable Conference on 11/13 and at the Industrial Food Forum on 12/1]
Diversifying & Improving Kaua‘i’s Non-native Forests by Planting of Useful Species
by Nicolai Barca on 2 November 2007
INTRODUCTION
The current situation on Kaua‘i, and most of Hawai‘i for that matter, is that the lowland areas where people frequent are covered in non-native invasive weeds, many of which are noxious and form impenetrable thickets. Their only major benefits to people are for their watershed value and game production for hunters, both of which they do relatively poorly. Fortunately, there are ways to
improve the situation while providing multiple benefits for everybody. Such benefits include improved watershed function, improved conditions for diverse recreational activities, edible fruit and nuts, as well as future timber resources.
By planting large, canopy-forming trees which are of low risk of becoming invasive, undesirable species can either be suppressed or completely replaced via shading. In this way it is possible to turn low diversity, low value forests into diverse forests full of useful tree species. Utilizing shade tolerant species and forest gaps reduces most of the work that would otherwise be needed to establish these trees.
It should be mentioned up front that in no way am I recommending planting in native forests (including uluhe) or planting species which risk invading into the remaining native areas.
POTENTIAL BENEFITS
1. Edible Products
A) Fruit and Nuts can provide food for both people and animals
B) Economic benefits derived from cash crops
C) Local products; reduce reliance on imports
D) On public land, products would be a public resource
2. Improved Watershed Function
A) Reduces negative impacts from feral pigs on watershed function. Diverse year round food sources means reduction in digging by feral pigs, which leads to reductions in erosion and stream sedimentation.
B) Open spaces though suppressing noxious weeds leads to reductions in pig trails and thus reductions in ground compaction, surface runoff, erosion and stream sedimentation.
C) Leaves of many species can act as a ground-cover improving rainwater infiltration into groundwater.
-Shade from canopy and leaf litter reduces water loss to evaporation.
-More water and potentially lower flood water levels. Water could potentially flow in areas where it usually would not such as dry stream beds on the leeward side.
D) Open conditions would allow for greater efficiency of hunters to control ungulate numbers.
3. Open Forest Conditions
A) shade from dense tree canopies can suppress or eliminate noxious weeds from under a tree.
B) reduce the need for trail maintenance and cutting trails through brush.
C) enhanced conditions for hiking, biking, camping, horseback riding, etc.
D) improved air flow
E) reduction in muddy conditions (pigs create a network of trails to move around in dense stands. (They can get very muddy).
4. Improved Hunting Conditions
A) diverse year-round food sources for game animals
B) healthier game animals
C) open forest condition favorable to hunting.
D) a lesser amount of muddy conditions.
E) reduced need for trail maintenance
F) encourage game animals to stay in more desirable locations and discourage seasonal migration patterns to remote and or native areas.
5. Future Timber Resources
A) wood for local craftsmen and possibility of a future timber industry.
B) shade tolerant trees reach for the light, forming a single strait, tall trunk favorable for timber harvesting.
C) many fruit and nut-producing trees are multipurpose and produce valuable timber as well.
6. Weed Buffer
A) reduced seeding potential of the present day invasive species forests to seed pastures, farmlands, backyards, and remaining native forests.
B) buffer against some new weeds which may invade forests.
C) buffer future native forest restoration plots from disturbance colonizing weeds.
7. Other benefits
A) flowers for lei making
B) feed for animals
C) neem for organic pest control in agriculture
D) implications in roadside weed suppression
WORKING WITH NATURE
This should be possible because of the same processes of ecological succession present in mainland continental forests. Most of Hawai‘i’s introduced invasive species are disturbance colonizers and are shade intolerant to some degree. In their homelands, many would be replaced by shade tolerant “older growth” species which would grow up through and shade them out. However, in Hawaii, those species are for the most part, absent in the forests.
Older growth trees are characterized by such non-invasive qualities as slow growth and producing few expensive seeds. Human hand is the only means for them to gain a fast foothold in Hawaii. The same qualities that make them un-aggressive also give them their usefulness, such as hard wood for timber and a large nutritious fruit.
Characteristics of Early Succession or Disturbance Colonizing Species:
A) Fast Growth
B) Produce many cheep seeds
C) Soft wood
D) Shade intolerant
Characteristics of Late Succession or “Old growth” species:
A) Slow growth
B) Produce few expensive seeds
C) Hard wood
D) Shade tolerant at some stage
ACTIONS TO TAKE
What areas can be planted and who can do it?
Just about anywhere that is overgrown with non-native vegetation can be planted. These include most forested valleys, forest reserves & public hunting areas, as well as brush covered undeveloped plots of land. Even if the land is destined to be developed, good looking fruit and timber trees might be spared and integrated into future landscaping of the property.
Planting can occur at the individual level or more organized levels such as clubs, organizational, private business, and government. For the individual planter, I suggest starting near home within ones own ahupua‘a. Fruit trees should be of good varieties if planted close to home or in areas where people are sure to use them. Lesser quality varieties should be saved for game production in hunting areas. Large seed avocado, although less desirable for food,
may have an advantage establishing under extreme shade conditions.
A note on legality: Land owner’s permission is required and a permit from the Division of Forestry and Wildlife (DOFAW) would be required to plant on state owned and/or managed lands.
PLANTING METHODS
1. Gap Planting
A) Find Alien Forest
B) Find or clear a gap
C) Maintain Gap until tree is established above canopy
D) New tree overtops and shades out understory
2. Use Shade Tolerant Species
A) Sow seed
B) Sapling reaches for light
C) Eventually reaches above canopy
D) New tree overtops and shades out understory
 3. Replacing Large Trees (i.e. Albizia)
A) Plant shade tolerant trees in understory around unwanted tree
B) Shade tolerant species establish in understory
C) Kill tree standing
D) New species fill in and suppress regeneration of seedlings
TREE LIST
Large Canopy-Forming Trees
Breadfruit (1)
Mango
Avocado (1)
Jackfruit
Lychee; Litchi
Eucalyptus spp.
Monkey pod
False Kamani; Indian Almond
Longon
Fijian Longon; Oceanic Lychee
Kamani
Norfolk Pine
Miscellaneous Pines
Citrus spp.
Tahitian Chestnut
Blue Marble (2)
Mahogany
Teak
(1) Breadfruit and Avocado can grow and fruit under albizia (Paraserianthes falcataria) as seen near Kalihiwai, Kauai. The trunk of the avocado can consists of a single strait trunk stretching for the light; ideal form for timber. The same traits are exhibited by breadfruit at this site.
(2) Blue Marble is a timber tree but possesses potential invasive qualities. Feral pigs feed on the nuts, which sprout and grow readily if not consumed. It is not recommended planting this species in areas where wild pigs are not common nor planting large quantities where they are.
Other trees which should be included
Koa
Ohia
Coconut
Milo
Kou
Macadamia nut
Soursop
Plumaria
Noni
Mt. Apple
Clumping bamboos
Hala
Maile
Kukui
Coffee
Cacao
Vanilla Vine
Dominant Non-native Vegetation on Kauai
Strawberry Guava
Common Guava
Shoebutton Ardisia
Downy Rosemyrtle
Melastoma
Java Plum
Albizia
Koa Haole
African Toulip
Hau Bush
Christmas Berry
Running Bamboos
Black wattle
Silk Oak
Clidemia
Lantana
Miscellaneous Grasses
Kiawe
Lantana
Guinea grass
CONTACT & BIO INFO
After growing up hunting and fishing on the north shore, Nicolai Barca graduated from Hawaii Community College in Hilo with a degree in Tropical Forest Ecosystem and Agroforestry Management. He is now employed by The Nature Conservancy protecting Kaua‘i’s best remaining native forests. His other interests are growing native plants, local politics in natural resource management, agroforestry, and organic gardening.
Nicolai Barca
Phone: (808) 443-9542
Email: nbarca@hawaii.edu
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