Ethical Forestry Ltd is currently being investigated by the Serious Fraud Office and according to Companies House is in liquidation.
Chris McCabe, group associate director at claims management company First Target Recoveries, said 872 clients who had invested in the company had been referred to it by the insolvency practitioner.
He said the majority of the clients he is dealing with held the investment with Liberty Sipp, but the provider has hit back at this claim, saying it is the victim of an "aggressive and sustained" misinformation campaign.
Liberty Sipp has claimed this misinformation campaign has led to investors becoming concerned about their investment, which it says it did sufficient due diligence on.
John Fox, director of Liberty Sipp, said: "While it is regrettable that the British company that marketed the Ethical Forestry investment scheme has failed, the underlying investment has not changed.
"Ethical Forestry SA continues to manage the tree plantations as normal and investors’ holdings are unaffected.
"However it is a fixed-term, illiquid investment and investors always knew they must wait until the trees on their plot are harvested before receiving their returns.
"Non-standard investments account for just 5 per cent of our clients’ assets, and as a responsible Sipp trustee, Liberty carried out extensive due diligence on the way the Ethical Forestry investment was structured before accepting any investments.
"We are now working to help any clients who did invest get the best deal."
He added that an "aggressive and sustained" misinformation campaign by several claims management companies had led to some investors becoming concerned about their investment.
In response to Liberty Sipp's claims, a spokeswoman from First Target Recoveries said: “We have been recommended to investors in the Ethical Forestry scheme by HJS Solutions, the liquidator appointed by Ethical Forestry Ltd.
“We are currently working with over 900 investors to recover mis-sold Sipp investments into the Ethical Forestry scheme.
“Following the sale of Ethical Forestry Ltd and subsequent announcement by HJS, we issued communications to our clients advising them of the next steps in terms of pursuing a claim where they had been mis-sold the investment.”
Mr McCabe said those who put cash into the forestry investment tended to have done so after a cold call introduced them to an adviser who was selling the scheme.
The minimum investment was £18,000 and Mr McCabe said at least 3,000 people invested in the Costa Rican tree plantation.
Mr McCabe said the overwhelming majority of the investments were made through self-invested personal pensions, with Liberty Sipp being the most common provider of schemes used to hold the forestry investment.