Seeds of survival — Acacia littorea at Binyalup too
Day 24 , a plant a day, Acacia littorea , Lowlands Coastal Reserve, 17 November 2020
I chose Acacia littorea for my plant of the day, as I noticed it eking out an existence in Albany, having self-seeded in the demolition site of the old Esplanade hotel which we were visiting this morning. Acacia littorea is also the wattle which grows the closest to my original path to the beach in Lowlands Coastal Reserve.
Pauly was asked to do the heritage survey for the proposed development of the old Esplanade hotel site. The Noongar elders on site consultation with the state development reps today included many stories of the lore of birds on the mounts, and the old corroboree ground in Adelaide Terrace, the creek waters and the former swamps connecting with Strawberry Hill and Lake Seppings and the Noongar name for Ellen Cove being Binyalup (not Binalup, dont forget the ‘y”, as important to pronounce with a “ying” sound). Binyalup means place of first light or place of the dawn. Hoping that the new infrastructure will incorporate the Noongar name Binyalup and Aboriginal artwork.
Returning home from the survey for my daily walk in Lowlands Coastal Reserve, I noticed that seed pods are appearing in the Acacia littorea, as I brushed past the hard prickly foliage on my old ridge path to the beach. Flowering is nearly over, with very few acacias bearing flowers, although the littorea acacias are not yet profusely bearing seeed pods.
The three new reveg patches are doing well in Lowlands Coastal Reserve. Our local reveg guru, Mark Parre, supplied many native seedlings including 2 acacia species of local provenance (Acacia littorea and Acacia myrtifolia). Acacia alata, Acacia pulchella and Acacia cyclops also grow in the Lowlands Reserve.
I enjoy acacias, and their shape changing nature, where the juvenile leaves are very different to mature leaves.
In contrast to the Wonnich featured on Day 22, which is the sole species in the Callistachys genus, there are 948 (almost one thousand!) different species of Acacia in Australia, at the last count. We have an active Sydney Golden Wattle busting group in our Lowlands community, as this invasive Acacia longifolia , is the one wattle not welcomed here.
The acacias are home to insects who make galls around seed cases and other plant parts. In Lowlands Reserve the Acacia myrtifolia are more likely to have insect squatters, but occasionally you can see galls on Acacia littorea. The gall making insects are possibly Cecidomyiinae species.
Wattles are bush tucker. In Menang country, the seeds of coastal wattles (mainly Acacia cyclops, Noongar name Gnaamarur) can be collected and ground up to make cakes and other edibles. The seeds have to be baked or heat treated — Don’t eat raw, and in WA, only Acacia cyclops, Acacia victoriae, and Acacia microbotrya, unless you have first hand knowledge. See https://pubmed.ncbi.nlm.nih.gov/31680210/
2014 research has suggested that , Acacia cyclops extracts, may possibly be therapeutic in treating breast cancer. See https://www.sciencedirect.com/science/article/abs/pii/S0960894X14007057
Seeds of survival indeed!
More references on food
Acacia cyclops is 27% protein, that’s more than chick peas or lentils. Though wattle seeds were found to contain some anti-nutritional factors, they can be reduced or deactivated by heat treatment prior to consumption or in the development of a new food product.
Acacia cyclops also has antimicrobial properties against E. coli and golden staph.
Chemical Composition and Anti-Nutritional Profiling of Wattle (Acacia cyclops, Acacia microbotrya and Acacia victoriae) Seed Originating from Western Australia
Chong, Wei Shan Cassandra ; Dykes, Gary A ; Coorey, Ranil Netherlands: Springer Science and Business Media LLC Plant foods for human nutrition (Dordrecht), 2019–11–03, Vol.74 (4), p.518–524
Acacia cyclops A. Cunn. ex G. Don
Mimosaceae
Rooikrans
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
Uses
Producing a dense high quality firewood, this species has been recommended for stabilization of coastal dunes. Goats and antelope browse the phyllodes. The seeds and their oily funicles are eaten by birds, primates, and rodents, and if crushed, might be suitable for cattle.
Folk Medicine
With its high tannin content, the species could serve as an astringent.
Chemistry
Bark has yielded 6.5% tannin, or in Natal, up to 12.1%. Seed contains 10% of fixed oil, the aril or funicle 40%.
Description
Dense, evergreen bushy shrub, often multistemmed, or small tree 3 to 8 m tall, with a rounded crown . In windy coastal sites it forms a hedge less than 0.5 m high. The foliage comprises light green phyllodes, varnished when young, and growing in a downward vertical position. Pods, maturing in summer, are not shed, but remain on the tree, exposing the seeds to predators and dispersers.
Germplasm
Reported from the Australian Center of Diversity, Acacia cyclops is reported to tolerate drought, salt, sand, weed, and wind.
Distribution
Native to southwestern Australia, where it grows mostly on coastal sand dunes. Used for stabilization in South Africa, it is spreading on sand and sandstone into coastal bush and heathland. This is an extremely weedy species spread by birds into indigenous vegetation. Once established, it is difficult to remove or replace. There is little vegetation cover beneath an Acacia cyclops thicket. The seeds remain viable in the soil for many years. It is relatively slow growing.
Ecology
Acacia cyclops can grow in dry areas with annual precipitation less than 300 mm. Tolerating salt spray, wind, sand-blast, or salinity, it is useful for dune stabilization. This species has a high light demand; it will not survive in deep shade. Monthly temperature means within the distribution range of this species vary from 5°C in winter to 31°C in summer. It is slightly resistant to frost. The species is generally found below 300 m altitude where annual rainfall is 200 to 800 mm. It grows on quartzitic or calcareous sand or limestone. It also is found in drier sites such as dune crests (NAS, 1980a).
Cultivation
Direct sowing of pretreated seed is recommended (NAS, 1980a). Seed are treated with abrasion, acid, and hot water treatment.
Harvesting
Trees may be harvested as needed. This species rarely coppices, and mature trees do not survive felling. The pods are nondeciduous and are therefore not easily gathered. Unlike many Acacia species, it is not considered a valuable tannin or gum producer (NAS, 1980a).
Yields and Economics
Standing biomass of Acacia cyclops in the southwestern cape of Africa, where it is replacing indigenous Fynbos vegetation and coastal shrub communities, was 131 MT/ha. Of this, the litterfall was said to represent 7.4% of the total biomass, 21.2% of the canopy mass.
Energy
Recommended by the NAS (1980a) as a firewood source. The wood is dense, the logs rarely exceeding 20 cm in diameter. It is a very popular firewood in South Africa, sold regularly in Cape Town. The annual litterfall of four Acacia species naturalized in the South African Cape, comprising 60% foliage and 30% reproductive structures, averages 7 MT/ha, double the value expected in evergreen scrub communities in winter rainfall regions. Standing biomass in the Acacia thickets is ca 10 times greater than that of mature Fynbos (11–26 MT/ha) and shrublands in other Mediterranean climates (15–30 MT/ha). Acacias lose ca 10% of their standing crop annually as litter, at a rate 3–4 times that of the Mediterranean heath and shrub communities. The litter accumulates on the ground. In a mature thicket, the dry mass of the ground litter per unit area exceeds that of the living canopy. The ground litter layer runs 14–28 MT/ha, which is fairly average by world standards. “The annual nitrogen and phosphorus input by Acacia litter should be about nine times as great per unit area as that of Fynbos.” Assuming an N content of 1.5% and a P content of 1.13%, Acacia litter would contribute 105 kg N/ha and 92 kg P. In an area where the annual precipitation averages between 500 and 750 mm/yr and the annual temperature average ranges between 16 and 18°C, with radiation averaging 450–500 Langleys/day (Capetown has an average annual precipitation of ca 600 mm, average temperature approaching 18°C), the total annual litterfall is 9,680 kg/ha, with 1.4% as flowers, 35.5% as pods, 5.3% as seed, 11.3% as twigs, 39.0% as phyllodes, and 7.7% unidentified fragments. The total standing biomass was 131 MT/ha DM, ˜±4% (Milton, 1981).
Biotic Factors
Most African Acacias are thought to be cross pollinated. Pests and diseases are not an important factor in South Africa; in fact, the lack of seed destroyers is partly responsible for the weediness of the species. Grazers may damage seedlings.
References
- N.A.S. 1980a. Firewood crops. Shrub and tree species for energy production. National Academy of Sciences, Washington, DC.
- Milton, S.J. 1981. Litterfall. of the exotic acacias in the southeastern cape. J. S. Afr. Bot. 47(2):147–155.
Complete list of references for Duke, Handbook of Energy Crops
Temperatures, Min 13 Max 25, no rain (highest temperature this month!) https://www.eldersweather.com.au/local-forecast/wa/lowlands
Writing this daily blog featuring a plant a day and walking daily is my fundraising effort for Bush Heritage #groundworkchallenge . To join my team or donate go to https://www.groundworkchallenge.org.au/fundraisers/sheilamurray/2020?fbclid=IwAR2HbNn0YsCCc3tiSK-_lbF5xLsssaD8wjGHaUwVYrRqYxM-kdJkijoj2N0
Lowlands Coastal Reserve is on Menang Boodja — country. I celebrate the strength, resilience and capacity of the Menang Noongar people who are the traditional owners of the land.
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