National Trust Wales chair Linda Tomos's climate challenge

A fresco by artist Thomas Wallace-Hay at the National Trust's Dyffryn House in the Vale of Glamorgan

Taking a lead in tackling climate change should be a priority for the National Trust (NT), says its new chief adviser in Wales.

Linda Tomos said the organisation would "lead the way" in promoting sustainable farming practices as well as innovative ways of generating energy.

She will become the first woman to chair the NT's Wales advisory board.

The charity is Wales' largest private landowner and also looks after 157 miles (252km) of coastline.

Ms Tomos said she was concerned at the loss of landscape and biodiversity in Wales and shared the view of the trust's director general Dame Helen Ghosh that climate change posed "the biggest challenge" to the charity in the future.

Coastal erosion, more frequent storms and an increase in bugs in the charity's stately buildings during warmer, wetter winters are having an impact.

The charity owns and manages several historic sites and their gardens in Wales, including Powis Castle, Penrhyn Castle, Tredegar House and Llanerchaeron.

The organisation, which describes itself as Europe's biggest conservation charity, has a plan to cut its energy use by a fifth by 2020 and generate half of it from renewable sources by the same year.

It has already installed a solar hot water system at Chirk Castle while Plas Newydd on Anglesey is home to Britain's largest marine heat pump, using water from the Menai Strait for its heating instead of oil.

The houses and their heirlooms require "very controlled environments" so finding new and innovative ways to ensure that any energy use is sustainable is vital, Ms Tomos explained.

She also said she wanted to prioritise the work of attracting new audiences to the trust's attractions and increase its offering in the Welsh language.

Recent initiatives have seen the charity offer tenancy of a farm on Llandudno's Great Orme for £1 a year, with the aim of promoting a conservationist approach.

Llyn Dinas lake was included in the £1m farm and estate in the Gwynant valley, bought in 2011

Dyffryn House and Gardens was re-opened after refurbishment in 2013

In 2015, NT bought land on Great Orme in Conwy, including the 145-acre Parc Farm

Meanwhile its scholarship programme for young farmers at Llyndy Isaf in Snowdonia's Nant Gwynant Valley is entering its fourth year.

Ms Tomos told BBC Wales the organisation's work with farmers was "absolutely vital" if it was to succeed in preserving "even more of our wonderful country".

"We're bringing back some natural farming practices which I think a lot of farmers in Wales are very comfortable with."

"A major challenge for us is that we have to look after the land we manage in perpetuity. We are unique in that respect - governments come and go, but the NT has to have strategies which ensure these wonderful places are secure forever in Wales."

Ms Tomos is currently chief executive and librarian for the National Library of Wales and will move to the NT at the end of June for a three-year term.

She replaces former chairman Keith James who said he had "enjoyed enormously working for the Trust in Wales", an organisation which "plays such an important part in Welsh life".