Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Platycladus (Thuja) orientalis; oriental arborvitae

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

1.03

Does the species have weedy races?

y=-1, n=-1

n

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

0

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

1

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

n

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

n

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

n

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

n

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

n

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

n

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

n

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

y

4.1

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

n

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

4

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

7.02

Propagules dispersed intentionally by people

y=1, n=-1

n

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

7.08

Propagules survive passage through the gut

y=1, n=-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

8.03

Well controlled by herbicides

y=-1, n=1

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

n

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

-6

Source

Notes

1.01

no evidence

1.02

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/var/apache/cgi-bin/npgs/html/tax_search.pl?Platycladus+orientalis (13 June 2002)

Distributional range:
Native: Asia-Temperate: China - Gansu, Hebei, Henan, Shaanxi, Shanxi; Korea
Other: naturalized elsewhere in China, native range uncertain [This statement is vague, since it is native to China and the native range is uncertain, how and they say it is naturalized in China??? could not find any evidence of naturalization from floras. In Florida, rare and not collected since 1905 (Wunderlin), not naturalized in New Zealand (Sykes)]

1.03

no evidence

2.01

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://gardenbed.com/p/2765.cfm

(1)Natural latitude range: Approximate limits north to south: 52°N to 22°N
List of countries with natural populations
Asia: China; Korea, DPR; Korea, Republic of; Mongolia; Myanmar
List of countries where planted
Asia: China, Japan
Africa: South Africa
North America: USA (2)cold stratification.

2.02

2.03

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.floridata.com/ref/P/plat_ori.cfm

Natural latitude range: Approximate limits north to south: 52°N to 22°N
Climate descriptors
- Altitude range: 10 - 3300 m
- Mean annual rainfall: 300 - 1600 mm
- Rainfall regime: summer
- Dry season duration: 3 - 7 months
- Mean annual temperature: 8 - 16ºC
- Mean maximum temperature of hottest month: 18 - 21ºC
- Mean minimum temperature of coldest month: 6 - 9ºC
- Absolute minimum temperature: > -50ºC (2)Oriental arborvitae occurs naturally in western China and North Korea, with an isolated population in northeastern Iran. It usually grows on steep, rocky hillsides and cliffs. USDA Zones 6 - 11.

2.04

CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.

Natural latitude range: Approximate limits north to south: 52°N to 22°N
List of countries with natural populations
Asia: China; Korea, DPR; Korea, Republic of; Mongolia; Myanmar
List of countries where planted
Asia: China, Japan
Africa: South Africa
North America: USA

2.05

CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.

Natural latitude range: Approximate limits north to south: 52°N to 22°N
List of countries with natural populations
Asia: China; Korea, DPR; Korea, Republic of; Mongolia; Myanmar
List of countries where planted
Asia: China, Japan
Africa: South Africa
North America: USA

3.01

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/var/apache/cgi-bin/npgs/html/tax_search.pl?Platycladus+orientalis (13 June 2002)

Distributional range:
Native: Asia-Temperate: China - Gansu, Hebei, Henan, Shaanxi, Shanxi; Korea
Other: naturalized elsewhere in China, native range uncertain [This statement is vague, since it is native to China and the native range is uncertain, how and they say it is naturalized in China??? could not find any evidence of naturalization from floras. In Florida, rare and not collected since 1905 (Wunderlin), not naturalized in New Zealand (Sykes)]

3.02

no evidence

3.03

no evidence

3.04

http://edis.ifas.ufl.edu/BODY_ST489

ittle invasive potential

3.05

no evidence

4.01

Dehgan, B. (1998) Landscape Plants for Subtropical Climates. University Press of Florida., Gainesville, FL. 638pp. p.33

4.02

no evidence

4.03

no evidence

4.04

no evidence

4.05

no evidence

4.06

no evidence

4.07

http://www.floridata.com/ref/P/plat_ori.cfm

Contact with the foliage of arborvitaes may cause dermatitis in sensitive individuals. [rare]

4.08

possibly, it is likely to be flammable like most conifers

4.09

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.floridata.com/ref/P/plat_ori.cfm

(1)"Chinese arborvitae is light-demanding, although saplings and young trees are somewhat more tolerant of shading. " (2)does okay in partial shade

4.1

(2) El-Sallami, I. H.; Makary, B. S. (2001) Growth and chemical composition of Thuja orientalis L. seedlings as affected by saline irrigation water, soil moisture content and soil type. Assiut Journal of Agricultural Sciences, 2001, Vol.32, No.3, pp.61-86, 50 ref.

(1) P. orientalis grows well on a variety of soils, even on infertile hilly soils or rock openings on sunny and dry slopes, but prefers neutral, acid or slightly alkaline soils.
(2) AB: The combined effect of saline irrigation (saline at 0, 2000, 4000 and 8000 ppm), soil moisture (80 and 120% of field capacity), and soil type (clay loam or sandy soil) on growth and chemical composition of T. orientalis was evaluated in the field (Assiut, Egypt), during the 1999 and 2000 seasons. Saline water at 2000 and 4000 ppm had no significant effect on most growth parameters. Salinity at 8000 ppm resulted in significant decreases in growth parameters. All salinity levels decreased leaf contents of N K, Mg and chlorophyll (chlorophyll a and b, and carotenoids). Sodium, Ca and total phenolic compound content increased with increasing salinity levels. P and total carbohydrate contents were not affected by salinity. Soil moisture at 120% of field capacity (high) decreased the damage caused by salinity, improved vegetative a

4.11

CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.

"tree up to 20m high, 1 m d.b.h."

4.12

no evidence

5.01

terrestrial

5.02

tree; Cupressaceae

5.03

no evidence

5.04

tree

6.01

no evidence

6.02

CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.

"It is mainly propagated by seeding"

6.03

no evidence

6.04

no evidence

6.05

Xing ShuPing; Zhang Quan; Hu YuXi; Chen ZuKeng; Lin JinXing The mechanism of pollination in Platycladus orientalis and Thuja occidentalis (Cupressaceae). Acta Botanica Sinica, 1999, Vol.41, No.2, pp.130-132, 5 ref.

probably wind-pollinated

6.06

no evidence

6.07

R. Criley, UH Department of Horticulture, personal communication

7.01

no evidence

7.02

CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.

Natural latitude range: Approximate limits north to south: 52°N to 22°N
List of countries with natural populations
Asia: China; Korea, DPR; Korea, Republic of; Mongolia; Myanmar
List of countries where planted
Asia: China, Japan
Africa: South Africa
North America: USA

7.03

no evidence

7.04

Dehgan, B. (1998) Landscape Plants for Subtropical Climates. University Press of Florida., Gainesville, FL. 638pp. p.33

"Woody cone to 1 inch; hooked at apex of each scale;1 to 2 wingless seeds per cone scale."

7.05

no evidence

7.06

http://hort.ifas.ufl.edu/trees/PLAORIC.pdf

does not attract wildlife

7.07

http://nmmastergardeners.org/Manual%20etc/Pdf%20FILES/Conifers%20and%20Pests.pdf

seeds drop when the cone ripens [might be dispersed by ground mammals]

7.08

no evidence

8.01

USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Fruit/Seed Abundance: Low
Seed per Pound: 22000

8.02

http://gardenbed.com/p/2765.cfm

Seed - best sown when ripe in the autumn in a cold frame. Stored seed germinates best if given a short cold stratification.

8.03

Talbert, R. E.; Klingman, G. L.; Saunders, P. A.; Howell, S. L. (1979) Evaluation of herbicides in field-grown ornamental crops, 1977 and 1978. Mimeograph Series, Arkansas Agricultural Experiment Station, 1979, No.271, 18 pp.

"Bentazone at 0.84 kg/ha, basally directed in 1-year-old oriental arborvitae (Platycladus orientalis), caused moderate injury. "

8.04

(1)http://gardenbed.com/p/2765.cfm (2)http://hort.ifas.ufl.edu/trees/PLAORIC.pdf

(1)any pruning that is carried out should be done with care[238]. Plants are susceptible to attacks by honey fungus (2)Arborvitae does not tolerate pruning well

8.05

no evidence