Seedlings and Weedlings
The Importance of seeding identification
Author: Rusty Linnane, Ecological Restorator
Published: Journal December 2021
In a world fast becoming aware of reforestation as a key to sustainability of the planet, more people are looking at Ecological Restoration or Bush Regeneration as a process to increase forest canopy within natural areas. Ecological Restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. This process is also proven to be more financially beneficial and achieves better environmental outcomes than Reconstruction, (planting seedlings in highly degraded areas) to create canopy.
The major objective of ecological restoration is to increase biodiversity; through assisting forest edges to expand through removing key threatening processes, such as environmental weeds and mimicking a natural disturbance of that edge. By creating disturbance on forest edges the seed bank that is in the soil and leaf litter will be activated to germinate, just like any natural disturbance. Along with the local native plant species seed germinating, species of environmental weed seeds present in the area will also germinate. Ecological restoration is the art of knowing where to assist these ecosystems and how to remove those threatening processes, such as weeds.
Weeds can be treated in any growth stage, yet the most environmentally and resource effective time to treat or remove weeds is at the seedling stage. Using less energy and more importantly less herbicide, seedlings or should we say, ‘Weedlings’ can be removed to allow native ‘Seedlings’ to establish. However, this poses a threat, as native seedlings can be difficult to identify, lost under annuals or mistaken for weedlings.
Native seedlings can be lost among the weedlings
Native pioneer Macaranga seedling among herbaceous annual weedlings
The loss of native seedlings from ‘off target’ damage can have an impact on the biodiversity of the ecosystem of your site. Within your site there may be limited numbers of a particular species. The loss of these specimens may result in them not being able to establish within the site, therefore decreasing biodiversity.
Therefore, seedling identification is vital to increase biodiversity when practising ecological restoration. The ability to correctly identify seedlings and weedlings increases the rate of native plant survival and speeds up the process of forest restoration. It will also help depleting the valuable native seed source that exists on
the site. Up until now this skill was learnt by years of practising ecological restoration or working in regeneration nurseries that propagate endemic species.
Seedling identification can be learnt whilst carrying out restoration works on the site. Becoming familiar with the species both native and exotic within the site are instrumental. Those botanical traits and characteristics that each plant possesses usually are present in the seedling stage; however, some specimens look completely different at seedling stage, especially compound leaved species. The key to identifying seedlings successfully is first becoming familiar with the mature species on the site, both native and exotic, look for immature specimens, possibly at sapling stage, then at seedling stage. Notice those telltale botanical characteristics that helped you identify the parent tree in the first place. When conducting maintenance of restoration sites look for differences in colour or shape, these little differences will assist your eye to quickly recognise changes and stop you from accidentally spraying out native species.
This practice can be challenging, yet rewarding, it can also provide some motivation when conducting strenuous restoration works. Noticing those desirable plant species are present on the site may be the stimulation needed to realise your efforts have not been in vain.
If you cannot identify these seedlings, let them mature a little until they disclose those identifiable features. Most plants will not set seed within a rotational visit, only some annuals can reproduce that quickly and they can even be beneficial to your site. Even Madeira Vine, one of the most invasive and structure threatening species will take months until it can produce a viable tuber.
If you do not know, let it grow
It is not critical to know every weedling on your site, learn the problematic weeds first that may be present within the vegetation communities you are working with. Those species that produce masses of seed in a very short period, species that can inhibit seedling growth or threaten the integrity of the existing vegetation and control them, some weed species can even be left and used to your advantage to create structure until native species establish.
As previously mentioned, native seedlings can be mistakenly removed when confused with exotic weedlings. During my career as a bush regenerator, I have noticed this on many occasions, and not just when working with trainees or volunteers, even experienced bush regenerators can make the same mistakes. These mistakes cannot just be attributed to inexperience or inappropriate operators; these mistakes happen because the similarity between native and some exotic species makes them look almost identical.
One of the most common environmental weeds on the east coast of Australia is Camphor Laurel Cinnamomum camphora, this plant is a member of the Lauraceae family. There are over 100 native Lauraceae species within Australia and many of them have very similar characteristics to Camphor Laurel, after all they are in the same family. Of these native Lauraceae species some look almost identical when at a seedling stage, and they will both occur in the same vegetation communities.
The common White Bolly Gum Neolitsea dealbata looks so alike that they are often mistakenly sprayed or removed because of these similarities. Both have the same leaf shape, size, coloration and even have the same prominent yellow venation distinguishable to the Lauraceae family, they even have the same glaucous underside of the leaf. Once about 200mm high the Bolly Gum’s leaves will have grown considerably, and any new growth will have a purplish brown appearance. Camphor leaves will always have that distinctive smell yet removing a leaf to crush and smell can be detrimental to a seedling, and this should be the final check. However, there are subtle differences and learning these key features can be achieved with experience.
Even the most common weed in Australia Lantana Lantana camara has its own doppelgangers, and they are both common pioneer species occurring after any disturbance. Native Mulberry Pipturus argenteus and Poison Peach Trema tomentosa both look similar to Lantana at seedling stage and are just another species incorrectly identified and mistakenly removed.
Recently I developed a series of training workshops to assist people in learning these identification skills and the seedlings and weedlings that are often mistakenly confused. Through a visual presentation and hands on practical experience, these workshops allow the attendee to identify the botanical features of common environmental weedlings and native pioneer seedlings. This stems from 20 years of instructing volunteers, trainees, and inexperienced bush regenerators to look for subtle differences and avoid off target damage when conducting ecological restoration.
So, get out into your site and get down to seedling level and look for those little gems hidden amongst the herbaceous weeds before you go furiously hand weeding or spraying.