Neil Heseltine acknowledged that the National Park faces a reckoning and pressures not faced since it was established in the 1950s due to changing views on land use in the countryside.
He referred to post-Brexit approaches to upland agriculture and how these policies can be aligned to climate change and ecological concerns.
Mr Heseltine also urged visitors returning to the Dales to book longer stays rather than day trips to support the local economy.
The open letter reads:
"After the trials and tribulations of a further lockdown, it is a huge relief to be in a position to properly welcome visitors back to the Yorkshire Dales from Monday.
"As government restrictions begin to ease and all of us are able to do a little more, it’s really important we stay aligned and on board with the roadmap for moving out of the lockdown so as not to undermine the incredible hard work that has been put into suppressing the Covid-19 virus this winter.
"The safety and wellbeing of our visitors and local communities is a huge priority for us and we would urge anyone planning a trip to the Yorkshire Dales to read the information and guidance on our website before travelling. It will help make a wonderful day even better as together we take these first cautious steps out of lockdown.
"Not since National Parks were established in the 1950s have they been seen as so important to the country. They are places for people to connect with nature and each other, to renew and restore their health and wellbeing, and to learn about the important relationship between town and country.
"We are acutely aware that many of you have been prevented from spending time in these places you love, with the people you love. We are also aware that many of you have lost loved ones to this dreadful disease.
"Last summer saw more people coming out into the National Park and it was excellent to see them and to acknowledge that the vast majority took away their litter, controlled and picked up after their dogs, heeded warnings not to BBQ, and showed great consideration towards our communities, our landscapes, and our wildlife.
"Throughout the lockdowns and reopenings, our farmers, landowners, partners, staff and volunteers have worked tirelessly to help care for this precious landscape - signposting footpaths, removing litter, making repairs and putting intensive cleaning measures in place to help keep the public safe.
"We are immensely grateful for all their efforts and, as a result, you will find a stunning landscape, with its historic landmarks, towns, and villages, here for us all to enjoy in the future.
"And thanks also to our amazing local businesses, many of whom continued to go above and beyond to adapt and make visiting the area safe. You can expect a familiar Dales welcome through the coming year.
"Please support these businesses by booking ahead wherever possible and, when the time is right, giving yourself the opportunity to sample some of the delicious produce and goods created here in the Dales. Consider coming for a stay not just for the day.
"Many of you know that, aside from the pandemic, there are other increasingly important forces of change that are acting on the nation’s landscapes which include the Yorkshire Dales National Park.
"The ecological and climate crises are at the forefront on the global stage and require us all to re-evaluate the way people and nature must co-exist. Following the UK’s exit from the European Union there are intense discussions taking place regarding the future of agriculture in the uplands and the opportunities available for it to play a huge part in nature recovery and climate change mitigation, as well as producing great food.
"Spending time in nature makes everyone feel better. It eases anxiety and promotes a sense of real wellbeing. Throughout this pandemic and beyond, we hope that the Yorkshire Dales National Park continues to be a source of sanctuary; solace; hope and sustainability for everyone."