Today is International Day of Forests. We celebrate the diversity and importance of our forests – some strange, others ancient, many young, and one commemorative – found in and around the Hauraki Gulf Marine Park.
- a large tract of land covered with trees and underbrush; woodland.
In fact, the definition for ‘society’ – a body of individuals living as members of a community – would be more accurate. If you’ve ever wondered how young saplings grow in deeply shaded parts of the forest without sunlight to photosynthesis, it’s because elder trees are caring for them. Much like we feed our young, adult trees are pumping sugar into the roots of saplings.
Sophisticated social organisers
New research suggests that trees are in fact far more alert, social and sophisticated than we thought. Forest trees have seemingly evolved to live in cooperative, interdependent relationships, maintained by communication and a collective intelligence similar to an insect colony.
How? Trees are communicating with one another and sharing resources through underground fungal networks, coined the ‘wood-wide web’. Not only that, they communicate by air too, using pheromones and other scent signals.
So, what on earth are they talking to one another about? Alarm and distress appear to be the main topics of tree conversation. They send distress signals about drought, disease and insect attacks, altering the behaviour of the trees they communicate with to ensure survival.
The complexity and marvels of forests don’t end there. We know that forests provide habitat for more than 80% of the world’s terrestrial species of animals, plants and insects. Forests work quietly in the background, cleaning our water, filtering our air and protecting us from climate change. They provide us with food, medicine and fuel. They are refuges from the stress of our modern lives.
More than a million reasons to love your Gulf
With 30 groups of islands and more than 400 individual islets found in the Hauraki Gulf Marine Park, forest diversity abounds. What’s more, of the 93 islands that are larger than 5ha, 47 are now predator-free and have undergone spectacular transformation to return back to the forests they once were. More than 1.5 million trees have been planted by volunteers on predator-free islands, providing safe forest havens for some of our most endangered native species.
But let’s start with the weird and wonderful flora that abounds on Rangitoto Island. Did you know that Rangitoto is home to the largest pōhutukawa forest in the world? Astounding when you consider that the island is essentially a lava field, relying entirely on windblown matter and the gradual breaking down of flora to create soil. As the pōhutukawa grow, they provide shelter and shade for other species like mingimingi, koromiko and puka, forming vegetation ‘islands’ that eventually join up. The pōhutukawa have even hybridised with Northern rātā to form many different iterations.
Next door on ancient Motutapu Island, the fertile ash that fell when Rangitoto was formed has helped the efforts of local iwi and the Motutapu Restoration Trust volunteers. These groups have planted more than 500,000 native saplings on 100ha of land since 1994. These pockets of regenerating coastal lowland forest – some of which are now over 7 metres high – provide habitat for more than 100 Coromandel brown kiwi, as well as tīeke/saddleback and pōpokatea/whiteheads.
Similar efforts have taken place on Motuihe Island/Te Motu-a-Ihenga by local iwi and the Motuihe Trust. Since 2003, volunteers have grown and planted thousands of trees on the island, one of the few places in the Park where tuatara are thriving in the wild.
The archetype for forest regeneration in the Hauraki Gulf Marine Park however is Tiritiri Matangi Island, one of the most successful community-led conservation projects in the world. Ten years of planting by thousands of volunteers since 1984 has increased forested areas from 6% to 60%, much of which is nearing maturity. This forest provides home and refuge for dozens of native species including giant wētā/wētāpunga and kōkako.
A two-stage process
Forest regeneration isn’t as simple as planting trees and walking away. It usually takes place in two stages. On Tiritiri Matangi ‘rapid-shade producers’ such as pōhutukawa, karo, coprosma, mānuka, harakeke, ngaio, and māhoe were planted initially. They provide shade for species that will eventually become canopy trees including pūriri, karaka, taraire, hīnau, kauri and so on, planted in the second phase.
Central to the forest regeneration on Motutapu, Motuihe and Tiritiri Matangi, was the establishment of plant nurseries on each island to propagate seed gathered from surviving trees and nearby locations – a practice called ‘eco-sourcing’. Alongside this, rigorous weed management ensures that these native species aren’t suffocated by, or competing with, invasive species.
Ancient forests and endemic species
The ultimate forest in the Park however, has to belong to Te Hauturu-o-Toi/Little Barrier Island – one of the last remnants of primeval New Zealand. It is the only large forested area left in the country relatively undisturbed by browsing mammals and is an invaluable refuge for rare and endangered plants, birds and animals whose mainland habitats have been destroyed. As such it can only be visited by permit to reduce the threat of invasion by predators and invasive plant species.
Distinct vegetation zones are present on the island, from the pohuehue covered boulders and pōhutukawa forest on the coastal fringe, through coastal kohekohe, pūriri and taraire forest, to 30-metre-tall kauri forest. Northern rātā and tawaroa predominate at mid-altitudes, while at higher altitudes, the cloud forest is dominated by tawheowheo, tawari and Southern rātā. Filmy ferns, mosses and liverworts abound in this moist environment created by the near constant envelope of cloud. The island is also home to over 400 native species, many seldom seen on the mainland such as the ominous-sounding ‘bird-catching tree’, named parapara, which can ensnare small birds with its sticky seeds.
Not to be outdone, neighbouring Aotea/Great Barrier Island can boast its very own type of kānuka (Kunzea sinclairii), differing from others of its genus by its trailing branches and silvery leaves. Aotea is also home to an impressive form of nikau, which have longer, lusher fronds.
A legend and a legacy
Forests also have cultural and historical connotations. Colin McCahon, one of New Zealand’s most prominent artists, was inspired by the kauri trees surrounding his home in west Auckland, painting numerous artworks on the subject. Sadly, many of the kauri at the McCahon house have dieback disease. In August 2018, Rotoroa Island gratefully received 30 kauri seedlings grown from disease-free seeds from these trees, to create a kauri forest in his legacy.
The threat of kauri dieback throws the interconnectedness and plight of our forests into stark light. What many people don’t know is that if we lose kauri, we lose the entire ecosystem around them. This is because they create their own soil type called a podsol in which at least 17 species depend on to survive. Respect their plight by sticking to the track and using the kauri dieback stations to clean your shoes on entry and exit to the forest.
Breathe, learn, and plant a tree
So, what can you do to help our native forests? First of all, spend time in them. Appreciate the tree dramas unfolding all around you at tree-pace. Slow down and breathe in the heady oxygen-rich air surrounding them. Learn more about our culture’s own unique connection to nature through rongoā Māori traditional healing, which uses the medicinal properties of native trees to restore health and wellbeing.
Winter is tree planting time, and many of the predator-free islands including Motutapu, Motuihe and Rotoroa host volunteer planting days that you can join. You’ll be contributing to the efforts of Auckland Council and many others to green Tāmaki Makaurau through the 1.5 Million Trees programme, and the Government’s wider One Billion Trees programme, aimed at delivering benefits for our environment, people, communities, and economy.
And into the forest I go, to lose my mind and find my soul. – John Muir
Next time you take a stroll in a forest, take a moment to truly see the community of trees you walk amongst. Wonder at their age, what they are saying to one another, what potential medicines they harbour, what species call them home. We collectively owe them so much and simply can’t live without them. In the face of rampant global deforestation, let’s plant, cherish and protect these sentient societies. They are truly nature’s cathedrals.