HELP: Distribution of Grevillea robusta Silky Oak
HELP: Distribution of Grevillea robusta Silky Oak - Southern Africa : Request for assistance in determining the distribution and prevalence of an the Silky Oak Grevillea robusta We are assessing the invasive potential of the Silky Oak in South Africa. In order to assess the appropriate categorization of the
Request for assistance in determining the distribution and prevalence of an the Silky Oak Grevillea robusta
We are assessing the invasive potential of the Silky Oak in South Africa.
In order to assess the appropriate categorization of the Silky Oak we need detailed information on its current distribution. We would like your help please.
In South Africa, trees of this species are used mostly as windbreaks and for agroforestry in farms and along roads and as a shade tree. They are also commonly used in parking lots and house yards as ornamentals.
The aim of this Masters project is to assess the invasiveness of G. robusta in South Africa by determining its distribution and rate of naturalization. And to to assess whether its inclusion as a Category 3 Invader under the National Environmental: Biodiversity Act (NEMBA, updated in 2014) is appropriate. We have observed that this species appears to be invading a number of areas from old cultivations in Mpumalanga and Gauteng provinces.
In order to assess the appropriate categorization of G. robusta, we need detailed information on its current distribution. And we would like your help please.
SPECIES DESCRIPTIONGrevillea robusta is a fast growing evergreen tree that belongs to the Protea family and is drought and cold tolerant. It is a semi-deciduous tree with a single stem that grows straight reaching heights of 20-30 m tall and a stem diameter of up to 0.8 m, Its canopy is cone-shaped and most branches grow at an angle of 45° at intervals of about 1 m. The bark grey on mature trunks.
Grevillea robusta has green leaves, 100-340 mm long and 90-150 mm wide with petioles 15-65 mm long. The fruit are 15-20 mm long on pedicels 15mm long).
In Australia, G. robusta has two commonly known habitats:
* small and discontinuous stands occur along river banks and streams, usually within 30 m from a river, on well-drained and fertile soil where water availability is moderate, and
We have observed them growing in similar habitats in South Africa and need to determine how widespread this is.
WHAT WE NEED: We need to know all current locations of Grevillea robusta and the number of individuals of various sizes at those localities.
For each observation we need:
* a photo of the tree to verify its identification.
* the number of individuals - separately for the following size classes: up to 1 m tall, 1-2 m tall, 2-4 m tall, 4-8 tall and taller than 8 m.
* a GPS coordinate for the locality.
HOW TO SEND US DATAPost it on iSpot.
Please place the number of individuals in the Description.
You may tag it as Alien. And if it is invading, please tag it "Alien, invasive"
You can monitor iSpot data for the project at http://www.ispotnature.org/projects/silky-oak
We would like to receive data by 30th of April 2017.
Your assistance will be highly appreciated and valued.
For any other details and information please contact:
Rabelani Marikhele [email protected], 079 664 9651
or Professor Kevin Balkwill, [email protected]
School of Animal, Plant and Environmental Sciences, University of the Witwatersrand