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

Cassia siamea (Senna siamea); Siamese cassia

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

y

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

2

2.02

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

2

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

y

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

y

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

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

y

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

n

4.05

Toxic to animals

y=1, n=0

y

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

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

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

y=1, n=0

n

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

2

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

y

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

n

7.08

Propagules survive passage through the gut

y=1, n=-1

y

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

y

8.03

Well controlled by herbicides

y=-1, n=1

8.04

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

y=1, n=-1

y

8.05

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

y=-1, n=1

Total score:

5

Source

Notes

1.01

no evidence

1.02

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

"To date it has been extensively cultivated throughout India, both within forest areas, and also in wasteland afforestation projects, for example in Uttar Pradesh, Bihar, Madhaya Pradesh, West Bengal and Gujarat; in these and in other states it has become naturalized. "

1.03

no evidence

2.01

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

Review of natural distribution
S. siamea is indigenous to southern India, Sri Lanka, Myanmar, Thailand, Malaysia and parts of Indonesia (Sumatra).
Natural latitude range
Approximate limits north to south: 25N to 5S

2.02

2.03

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://pppis.fao.org/

(1) S. siamea is indigenous to southern India, Sri Lanka, Myanmar, Thailand, Malaysia and parts of Indonesia (Sumatra).
Natural latitude range
Approximate limits north to south: 25N to 5S
Climate
S. siamea is capable of growing under a wide variety of climatic conditions ranging from humid through to arid. It has been grown in regions with low rainfall (500 mm in Cyprus) and high rainfall (2800 mm), and can endure a dry season which may last 4 to 6 months. In India, a minimum of 1000 mm rainfall is recommended for good development (Troup and Joshi, 1983).
In its natural habitat, the absolute maximum shade temperature varies from 24-36C. It can grow at altitudes of up to 1380 m (Von Carlowitz, 1991). Mean annual temperature is within the range 20-28C (Heinsleigh and Holaway, 1988).
A modified description of climatic requirements (see climatic data table of this data sheet) was prepared by CSIRO (see Booth and Jovanovic, 2000).
Descriptors
- Altitude range: 0 - 1380 m
- Mean annual rainfall: 500 - 2800 m

2.04

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

Review of natural distribution
S. siamea is indigenous to southern India, Sri Lanka, Myanmar, Thailand, Malaysia and parts of Indonesia (Sumatra).
Natural latitude range
Approximate limits north to south: 25N to 5S

2.05

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

Location of introductions
S. siamea was originally introduced mainly as an avenue shade tree for roadside planting. To date it has been extensively cultivated throughout India, both within forest areas, and also in wasteland afforestation projects, for example in Uttar Pradesh, Bihar, Madhaya Pradesh, West Bengal and Gujarat; in these and in other states it has become naturalized. It is planted in degraded and dry areas for rehabilitation of forests and holds promise for reclamation of mined areas (Shyam Lal, 1991). It has also been planted in areas of river valley projects.
The species has been introduced into East Asia, Cyprus, Africa and the New World.

3.01

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

"To date it has been extensively cultivated throughout India, both within forest areas, and also in wasteland afforestation projects, for example in Uttar Pradesh, Bihar, Madhaya Pradesh, West Bengal and Gujarat; in these and in other states it has become naturalized. "

3.02

no evidence

3.03

no evidence

3.04

no evidence

3.05

Noxious Weed List, Search the Weeds Australia Database. Webpage available at: <http://www.weeds.org.au/noxious.htm>

5 Senna spp. are listed as noxious weeds in Australia

4.01

no description of these traits

4.02

(1) AB: Research on the allelopathic effects of C. siamea , A. microsperma and Leucaena glauca [L. leucocephala ] (used as shade trees for cocoa) on cocoa clone ICS 60 was conducted in greenhouses at the Indonesian Coffee and Cocoa Research Institute, using the Salisbury & Ross method. Cocoa seedlings were grown in polybags for 1 month and then watered with leachate from growing medium in which C. siamea , A. microsperma or L. leucocephala had been growing for 2 months. Control plants were watered with ground water and other set of seedlings were treated with leachate from growing medium without plants to assess the effects of the nutrients supplied from this source. Every 2 days, each seedling was treated with 200 ml leachate/water. Leachate from C. siamea and A. microsperma retarded cocoa growth, but that from L. leucocephala did not. Stem expansion and dry weight increase were significantly inhibited. The leachate from the growing medium without plants increased cocoa seedling growth indicating that the i

4.03

no evidence

4.04

(1)Hitinayake, H. M. G. S. B.; Ratnayake, R. M. W. R. (2000) Secondary forests in the dry zone as a source of tree fodder. Gunasena, H. P. M. (editor) Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka. 2000, pp.78-90, 2 ref. (2)http://www.winrock.org/forestry/factpub/FACTSH/S_siamea.html (3)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.

(1)" Wa (Cassia siamea ), Ehela (C. fistula ), Seru (Premna tomentosa ), Burutha (Chloroxylon swietenia ) and Wal Kurundu (Cinnamomum litsaeaefolium ) were the species having high population density due to low palatability to goats and cattle." (2)The leaves and seeds can be eaten by ruminants (3)Grazing livestock can severely damage small trees

4.05

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)Little and Wadsworth. 1964. Common trees of Puerto Rico and the Virgin Islands. USDA Forest Service Handbook No 249

(1)"The leaves, pods and seeds may be eaten by pigs, but are toxic to them." (2)As hogs relish the poisonous leaves, farmers in Puerto Rico have suffered losses

4.06

(1) CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.
(2) Michael F. Schneider, (1999). Lepidopteran Pests. Webpage available at: <http://www.fzi.uni-freiburg.de/InsectPestKey-long%20version/lepidopt.htm>

(1) Protection
S. siamea is fairly resistant to termites but is susceptible to scale insects, caterpillars (Eurema blanda) and defoliating insects (Heinsleigh and Holaway, 1988). Some of these pests are: Catopsilia crocale, which defoliates young plants; Xyleutes persona, a bee-hole borer; Indarbela sp., a caterpillar which damages bark; Celosterna scabrator, which bores tunnels in the stem and roots; and caterpillars of Labdia sp., which bore into dry pods.
Among the fungal diseases, Ganoderma lucidum causes spongy-rot and butt rot. Fomes lucidus is a parasitic wound fungus that invades the tree through the roots, causing a white soft decay in the lower stem. After the tree dies, the blood red sporophore appears. Phaeolus manihotis [Polyporus baudonii] is a serious root disease causing dieback.
Suggested control of pests and diseases includes biological control by parasites and predators, slow release insecticides, use of pheromones and silvicultural methods.
Grazing livestock can severely damage small tr

4.07

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

"Contact with wood shavings irritates the skin. " [such contact would rarely occur]

4.08

http://www.winrock.org/forestry/factpub/FACTSH/S_siamea.html

Probably not because it is a single trunked evegreen tree.

4.09

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

"S. siamea is a strong light demander and is sensitive to poor drainage."

4.1

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.winrock.org/forestry/factpub/FACTSH/S_siamea.html

S. siamea is not exacting in soil requirements, but prefers moist soils with good drainage (Troup and Joshi, 1983) and a soil pH of 5.5-7.5 (Gutteridge, 1997). In West Bengal, it has been grown in lateric soil after deep soil working. It tolerates denuded shallow soils (Hocking, 1993), but its growth will stagnate in dry areas, with the tree becoming stunted after 4 to 5 years; coppice growth will also be reduced. S. siamea is suitable for use on vertisols, xerosol/calcisols, aerisol/alisols, ferrasols, and nitosol/nitisols (FAO classification). It flourishes on both flat terrain and hill slopes,
Descriptors
- Soil texture: light; medium; heavy
- Soil drainage: free
- Soil reaction: acid; neutral
- Special soil tolerances: shallow; infertile
- Soil types: fluvisols; ferralsols; alfisols; lateritic soils; nitisols; vertisols; calcareous soils (2)Best growth occurs in deep, well drained, rich soils with pH 5.5-7.5. It tolerates well drained lateritic or limestone soils and moderately acid soils (pH 5.

4.11

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

"S. siamea is a medium-size tree rarely exceeding 20 m in height, more usually 10 to 12 m. "

4.12

no evidence

5.01

terrestrial

5.02

tree; Fabaceae

5.03

(1)CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.winrock.org/forestry/factpub/FACTSH/S_siamea.html

(1)"It is now well accepted that S. siamea does not fix nitrogen through Rhizobium symbiosis in nodules, although there is some evidence that nitrogen-fixing activity may occur in the warty, lenticellate bark (Gutteridge RC, 1997. Senna siamea (Lamk.) Irwin & Barneby. In: Faridah Hanum I, Van der Maesen LJG, eds, 1997. Plant Resources of South-East Asia. No. 11. Auxillary plants. Leiden, Netherlands; Backhuys.)." (2)a nonnitrogen-fixing leguminous tree

5.04

tree

6.01

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

There are no records of ex situ conservation of S. siamea. As it is common within its natural distribution range, and is planted extensively, it does not seem to be endangered, nor is it considered liable to genetic erosion (Sosef et al., 1998).

6.02

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

"For stump plant production, seeds are sown in beds in lines about 23 cm apart. Germination starts 1-4 weeks after sowing. "

6.03

no evidence

6.04

no evidence

6.05

[http://www.barbadine.com/pages/cassia_siamea_lien.htm]

no evidence [Picture of flowers does not suggest adaptation to specialist pollinators]

6.06

no evidence

6.07

http://216.239.57.100/search?q=cache:InuxTDodBRMJ:www.dfsc.dk/pdf/
Seedleaflets/Senna%2520siamea_int.pdf+Senna+siamea&hl=en&ie=UTF-8

Flowering and fruiting begin at the age of 2-3 years

7.01

no evidence

7.02

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

Location of introductions
S. siamea was originally introduced mainly as an avenue shade tree for roadside planting. To date it has been extensively cultivated throughout India, both within forest areas, and also in wasteland afforestation projects, for example in Uttar Pradesh, Bihar, Madhaya Pradesh, West Bengal and Gujarat; in these and in other states it has become naturalized. It is planted in degraded and dry areas for rehabilitation of forests and holds promise for reclamation of mined areas (Shyam Lal, 1991). It has also been planted in areas of river valley projects.
The species has been introduced into East Asia, Cyprus, Africa and the New World.

7.03

no evidence

7.04

http://www.dfsc.dk/pdf/Seedleaflets/Senna%20siamea_int.pdf

no evidence [indehiscent pod ..'.When the pods have turned brown, they can be harvested from the tree. It is also possible to collect mature, half opened pods from the ground.' This probably suggests dispersal by gravity. No evidence of adaptive structures for wind dispersal]

7.05

no evidence

7.06

no evidence

7.07

no evidence

7.08

http://www.winrock.org/forestry/factpub/FACTSH/S_siamea.html

seeds can be eaten by ruminants [with hard seed coat]

8.01

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

"There are between 35,000 and 41,000 seeds per kilogram (Sosef et al., 1998). The number of plants that can be expected from a kilogram of seeds is about 32,200.
"; "Pods are flat, 15 to 25 cm long, soft and ribbon-like when young, brown when ripe, indented between the seeds; there are 20-30 seeds per pod. Seeds are bean-shaped, shiny dark-brown, 8 mm long."
[requires 33-50 pods per squaremeter, not often likely]

8.02

(1) CAB International, (2000) Forestry Compendium Global Module. Wallingford, UK: CAB International.
(2) Kamara, A. Y.; Akobundu, I. O.; Chikoye, D.; Jutzi, S. C. Weed seed bank size and composition in an arable crop mulched with pruning from three multipurpose trees in Southwestern Nigeria. Angewandte Botanik, 1999, Vol.73, No.1/2, pp.25-30, 31 ref.

(1) "S. siamea seeds are orthodox, and will keep for several years in dry storage at ambient temperature (Heinsleigh TE, Holaway BK, 1988. Agroforestry Species for the Philippines. Manila, Philippines: US Peace Corps, AJA Printers.8). "; "It regenerates naturally by seed, and seeds may lie dormant on the ground for many years until favourable conditions occur for germination. It has spread naturally in the dry deciduous forests of southern India, and is reported to regenerate naturally in West Bengal."
(2) AB: Weed seed bank size and composition were analysed in 1995 and 1996 in maize fields mulched with prunings from Gliricidia sepium , Leucaena leucocephala and Senna siamea in south western Nigeria. In the first year of cropping there were 87, 78 and 79% more weed seeds in the unmulched plots than in the G. sepium , L. leucocephala and S. siamea mulched plots, respectively. In the second year of cropping, the weed seed bank at 0-5 cm soil depth was higher than in the first year in the G. sepium and L. leu

8.03

no evidence

8.04

http://www.winrock.org/forestry/factpub/FACTSH/S_siamea.html

Plantations can be managed by coppicing, lopping, or pollarding, For mulch or leaf production, the first cut may be 12-18 months after sowing, followed by 3-4 cuts per year thereafter

8.05

FACT Sheet, FACT 99-04, (June 1999) Senna siamea - a widely used legume tree. Webpage available at <http://www.winrock.org/forestry/FACTPUB/FACTSH/S_siamea.html>
Written by Dr. Mohammed Kamal Hassain, Associate Professor, Institute of Forestry and Environmental Sciences, Chittagong University, Chittagong 4331, Bangladesh.
A publication of the Forest, Farm, and Community Tree Network (FACT Net)
Winrock International
FACT Net
38 Winrock Drive
Morrilton, Arkansas 72110-9370 USA
Phone: 501-727-5435
Fax: 501-727-5417
Email: forestry@msmail.winrock.org
www.winrock.org/forestry/factnet.htm

No significant pest or disease damage has been recorded, but minor damage can be caused by the wood rot, Ganoderma lucidum (Khan and Alam 1996). Insects that damage seed include Caryedon lineaticollis and Bruchidius maculatipes. Seed-borne fungi reported in Thailand include Aspergillus niger and Curvularia pallescens (Hor 1993). The fungus Phaeolus manihotis occasionally causes damage to the root system (Gutteridge 1997).