A £640 million Nature for Climate fund would increase tree planting in England, with the Government aiming to work with the devolved administrations to boost tree-planting rates to 30,000 hectares every year, which the party said could mean 30 million more trees.
Under the plans, new forests would spring up and existing woodland like the Northern Forest and Northumberland Forest would be expanded, while more trees would also be planted in towns and cities.
The fund would also be used to restore degraded peatland across the country, the party said.
A Conservative government would also launch a £500 million Blue Planet fund, resourced from the International Aid budget, to export UK expertise in marine science around the world, supporting developing countries to protect marine habitats.
The party said funds would also be used to improve conditions for fishing crews who rely on healthy oceans and plentiful fish stocks for their livelihoods.
Mr Johnson said: "There is nothing more conservative than protecting our environment and these measures sit alongside our world-leading commitment to net-zero greenhouse gas emissions by 2050.
"But, just as with our planned investment in schools and hospitals, we can only do any of this if we end the gridlock and deadlock in parliament with a Conservative-majority government."
Sue Hayman, Labour’s shadow environment secretary, said: "This is yet more proof that you can’t trust the Tories to tackle the climate and environment emergency."This new pledge only amounts to 1% of the trees the Committee on Climate Change says we need to plant if we’re to limit dangerous global heating and protect the planet, and with the Tories desperately failing on their previous target of planting 11 million trees - with only a third planted so far - it’s clear that they aren’t serious about this agenda.
"When Labour comes forward with its own ambitious proposals as part of our Plan For Nature, they will be informed by what the science says is necessary and possible – not by what Boris Johnson thinks he needs to do to greenwash his atrocious environmental record."