climbing redwoods is forbidden in most places, but in this reserve we have special permission and what a privilege it is. 0k, a0 metres. i can t get over how beautiful this tree is. we have button for the canopy, so there are burn marks on this tree at a0 metres, which boggles my mind. it s incredible up here. anthony told me that wildfires are another threat these trees are increasingly facing in the modern world. a bird s nest. i don t think there s anybody home. with anthony already at the top collecting samples, i make my final push upwards. this view is definitely one of the wildest, most incredible views i ve seen in my entire life. i can t believe i m 71 metres off
temperatures are increasing, it s drying things out as temperatures get warmer, and that s a big, big consideration for these particular trees. because they need so much water, that s affecting their water balance and their ability to transport more water to the tops of the trees. but now it s time to get to work. there we go. so first, we need a sample of the tree s core. this is the halfway mark here and then we move it to the ground. we ll be able to pull that spoon out with the core on it. earlier on, anthony showed me some of those secrets this tree had already revealed. and so, wow, these are the rings here? yeah, yeah. each one of those is an annual ring one year s worth of growth. you can see here, you know, there could be 100, 200, 300, 400, 500, 600, 700 maybe years here. wow. so this section up here hasn t seen sunlight for 600, 700 years? yeah. this redwood stands at over 70 metres tall.
and that s far more rewarding than taking a selfie to share with your friends. and finally, when i met a couple who have dedicated their lives to raising awareness of one of the world s most spectacular migrations. you wouldn t know it to look at, but these hills arejust a couple hours drive from mexico city, one of the world s biggest urban conurbations. this is the transatlantic volcanic belt, but it s not the volcanoes we ve come to see. every winter, millions of butterflies fly for around two months from canada and the us to a few patches of high altitude forests here in mexico. in recent years, the populations have dwindled, thanks to the destruction of habitats in the us and canada and deforestation here in mexico. one study says the numbers have gone
listen, it s no secret that our collective globe trotting has had an impact on our world for several years now something we always think about here on the travel shows. so the plan today is to look at some of our favourite episodes that have tried to shine a light on the issue. first up, a personal highlight of mine on the california coast when i went to the stretch known as big sur to understand more about the effects of climate change. from the top of the world s tallest trees. for over a millennium, redwood trees have become an icon of this state. so these are coast redwoods. they are the tallest tree species in the world, reaching currently about 380 feet tall. as the tallest ones, they re really important ecologically. they support the habitats and provide habitat for a lot of plants and animals. so as the climate changes,
this crisis is going to be over know exactly when and we don t know exactly when the stock market will reach its bottom, we ve got to be prepared for this to last a long time. if you assume that you re out of work for nine months but you end up only being out of work for three, well that s great. but if you think you re going to be furloughed for three months and it lasts for nine, well that ll be emotionally devastating. so, we ve got to prepare ourselves. tangibly and practically, as well as psychologically and emotionally. california u.s. senator